Let us start with a current list of the new errata. Feel free to comment on these, as well as to continue to add new ones.
Ars Magica Fifth Edition, Second Printing
Bjornaer Template (p. 24): Replace "Blunt the Viper's Fangs" with "Agony of the Beast".
Affinity with (Ability) (p. 40): Replace "Study Totals" with "Advancement Totals".
Affinity with (Art) (p. 40): Replace "Study Totals" with "Advancement Totals".
Apt Student (p. 40): Replace the second sentence with "When being taught by someone else, add five to the Source Quality".
Elemental Magic (p. 41): Add the following sentence to the first paragraph. "If you gain experience in more than one Form in a single season (perhaps from Adventure experience), you gain a total of one free experience point in each Form, no matter how many Forms receive experience from the season."
Failed Apprentice (p. 42): Delete the sentence "You may learn Magic Theory and serve a magus as a laboratory assistant."
Good Teacher (p. 43): Replace "Advancement Total" with "Source Quality".
Mercurian Magic (p. 46): Replace all occurences of Wizard's Communion with Wizard's Vigil.
Unaging (p. 50): Replace the fourth sentence with "You may die from terminal and potentially fatal crises, according to the normal rules."
Deficient Form (p. 53): Change "study totals" to "Advancement Totals".
Deficient Technique (p. 53): Change "Study totals" to "Advancement Totals".
Incomprehensible (p. 55): Change "Study Total" to "Advancement Total".
Specializations (p. 62): Replace the first sentence with "Each Ability you select for your character, except Spell Mastery, should be assigned a specialization".
(Living Language) (p. 66): Add the following sentences to the paragraph after the list of competences by score. "Two dialects of the same language generally have a –1 penalty. If your character is not specialized in a dialect, you should specify a dialect without specializing in it, and take the penalty when conversing with people who speak a different dialect. If you speak a "standard" version of the language, that is a dialect that differs from all other dialects."
Sense Holiness and Unholiness (p. 67): Replace the slightly confusing text about demons and angels with "The Ease Factor to detect a demon is 0, but the character must still Penetrate its Magic Resistance (see page 184). If an angel is hiding its divine nature, which is unusual, the Ease Factor is 15, and the character must Penetrate. If the angel is not hiding its divine nature, the roll automatically succeeds.".
Library (p. 71): Replace the antepenultimate sentence with "Summae have a level, and once a character's level in the subject of the book equals that level, the book is no longer of any use."
Spell Mastery (p. 86): Add the following sentence to the end of the first paragraph. "Spell mastery Abilities are their own category, and Virtues that give characters access to other categories of Ability do not cover spell mastery Abilities. They may only be learned by characters who use Hermetic magic to cast spells."
Fast Casting (p. 87): Add the following sentence. "This special ability may not be taken for Ritual spells."
Multiple Casting (p. 87): Add the following sentence at the beginning of the second paragraph. "All copies of the spell are cast simultaneously, and the action counts as a single casting for the purposes of Concentration and similar concerns." Replace "spell" with "copy" throughout the paragraph. Add the following sentence at the end of the paragraph. "Any other, special, cost associated with casting the spell must be paid for each copy."
Multiple Casting (p. 87): Add the following paragraph at the end. "This special ability may be taken for Ritual spells. The casting time is that for a single spell, but one pawn of appropriate vis per magnitude of the spell must be expended for each copy. The normal limit on pawns of vis expended (the maga's score in the Art) applies. Fatigue levels lost convert to wounds, as normal for Ritual spells."
Longevity Rituals (p. 101): Add the following sentences to the final paragraph of this section. "A Longevity Ritual performed for someone else also fails when the subject suffers from an aging crisis. If the subject is a magus and has access to the Laboratory Text, he may perform the ritual himself. (Vis usage is limited by the magus's Arts, as for a spell, which may make it impossible.) As the magus was present for the original creation of the ritual, and quite possibly assisting in it, he understands the shorthand. A subject who is not a Hermetic magus may not repeat the ritual. Any magus with access to the Laboratory Text may do this, but a magus who was not involved in the initial creation needs an accessible Laboratory Text."
Writing Laboratory Texts (p. 102): Add the following paragraph at the end of the section. "Any person who assisted in a particular Laboratory Activity, adding their Intelligence + Magic Theory to the Lab Total, understands the Laboratory Texts produced for that activity without needing to translate them, and may make generally accessible copies. This also applies to a magus who is the subject of a Longevity Ritual created by another magus, even if he does not assist. Assistants do not, however, create Laboratory Texts.""
Using Laboratory Texts (p. 102): Replace the first sentence of the first paragraph with "A magus who has a Laboratory Text for a particular effect may reproduce it in a single season if his Lab Total equals or exceeds the level of the effect.". Replace the third sentence with "A magus may reproduce multiple effects if they are all of the same Technique and Form, and the total of their levels is no greater than his Lab Total.".
Shared Senses (p. 105): Change the base level to share a single sense to five, and the final level to 20.
Extraordinary Results (p. 108): Add the following sentence at the end of the first paragraph. "The level of the effect is not changed by any extraordinary result, nor does it gain any requisites. This may result in a spell or effect that is more or less powerful than a conventional Hermetic effect of its level."
Aquam Spells (p. 121): Change the size of the puddle of corrosive liquids to half a pace across and a fifth of a pace deep.
Wind at the Back (p. 128): Replace "D: Sun" with "D: Special".
Endurance of the Berserkers (p. 134): Delete the final paragraph of the spell description.
Object of Increased Size (p. 154): Change the level to 20, and add "+1 stone" to the level calculation.
The Trackless Step (p. 155): Add the following sentence to the spell description. "This spell does not quite fit conventional Hermetic guidelines, and may have been the result of experimentation in its original invention. Troupes may choose to require magi to find a Lab Text in order to invent it."
Wizard's Communion (p. 160): Replace the final sentence of the first paragraph as follows. "One of the magi in the group must also know the specified spell, or cast it from a Casting Tablet." Replace the first sentence of the second paragraph as follows: "Only one magus in the group needs to cast the spell, but it must affect all the magi (by Penetrating their Magic Resistance). The magus who casts the Wizard's Communion need not be the one who casts the main spell, and normally it is better for them to be different. More than one magus in the group may cast the spell. In this case, add the total levels of successfully cast Wizard's Communion to get the effective level of the Wizard's Communion for this casting."
Muto Vim Spells (p. 160): After Wizard's Reach, add: Wizard's Vigil. R: Voice, D: Sun, T: Group. This spell functions as Wizard's Communion, except that the longer duration allows it to be used with Ritual spells. For the purposes of its effect, treat it as a Wizard's Communion of two magnitudes lower.
Advancement (p. 163): Change the sentence after the formula to say "A character may only gain experience from one source (one book, one teacher, one set of adventures) in one season."
Adventures (p. 163): Add the following sentences to the end of the first paragraph. "Note that the Source Quality is for the whole season, no matter how many adventures happen in a season. (Multiple adventures in one season would be a good reason to set a Source Quality of 10, however.) Similarly, an adventure that takes more than one season may serve as a source of experience in each of those seasons."
Practice (p. 164): Replace the formula call-out as follows: Practice Source Quality: 4–8, usually 4
Summae (p. 165): Replace the final sentence of the third paragraph as follows. "This bonus cannot exceed the base quality of the summa, so the final quality cannot be more than twice the sum of the author's Communication + bonuses from Virtues + 6."
Copying Books (p. 166): Replace the third sentence of the first paragraph as follows. "When she has accumulated points equal to the level of an Art summa, or five times the level of an Ability summa, it has been copied."
Combat: Simple Example (p. 172): In the penultimate paragraph, the damage to Polandrus is 9 points, not 10. Change the last three sentences of the paragraph to read "This gives Ignatio an Attack Advantage of 8, which after accounting for Ignatio's Damage and Polandrus's Soak works out to 9 points of damage (note that Polandrus's Wound Penalty does not apply to Soak because Soak is not an action). This inflicts a Heavy Wound on Polandrus, adding another -5 to his Wound Penalty. The wolf is now at -6 to all actions."
Weapon Tables (p. 176 and 177): Change "The modifier to X" to "The Weapon X Modifier" in the tables.
Wound Penalty –3 to –5 (p. 179): Replace "Study Total" with "Advancement Total".
Fire Guardian (p. 4): Change the calculation from "+3 environmental trigger" to "+3 linked trigger". Add a new paragraph: "InIg 19 (Base 2, +1 Touch, +2 Sun, +2 Room, +1 two uses per day, +3 environmental trigger)"
Broken Covenant of Calebais
Crenvalus, Magister of Control (p. 75): Tossing the Brawling Brute should be Base 10, level 20, and Topple the Brutish Band should be Base 10, level 30.
Guardians of the Forests
Trust of Childlike Faith (p. 21): Change the Arts to PeMe and the Casting Total to +12.
Eye of the Eons (p. 21): Change the name to "Eyes of the Eons", and the level to 10.
Chaos of the Angry Waves (p. 23): Change the level to 30.
Immortality of the Forest (p. 38): Change the type of the Virtue to Supernatural.
Philippus Niger (p. 60): Replace his Encumbrance with 1 (1). Chaos of the Angry Waves is level 30.
Imanitos Mendax (p. 73): Change his Dagger Attack score to +3. Rename "Disguise of the Transformed Wizard" to "Disguise of the Transformed Image", and change the Casting Total to +24. Change the level of Recollection of Memories Never Quite Lived to 4.
Falke (p. 96): Change the level of Chaos of the Angry Waves to 30.
Ioannes Acer (p. 106): Reduce Encumbrance to 2 (3). Change the level of Piercing Shaft of Wood to 10, and the level of The Treacherous Spear to 25.
Hilda (p. 117): Change Short bow Init to –3 and Grapple Damage to n/a.
Byrek (p. 119): Change Fist Defense to +6. Change his Encumbrance to 3 (3), and reduce all Init values by 1.
The Corruption of the Merovingians (p. 137): Delete the reference to Hildegard of Bingen.
Houses of Hermes: True Lineages
Perdo Vim Guidelines (p. 75): Replace the second guideline with "Gen: Dispel a Hermetic enchantment with a level less than the guideline level used + 5 + a stress die (no botch). The spell must be a Ritual."
Minstrels and Wanderers (pp. 91-93): On page 93, delete the sentence referring to "Larta magi".
Cataphract and Wili (p. 127): Replace the Wound Penalties for each ghost as follows: –1 (1–5), –3 (6–10), –5 (11–15), Incapacitated (16–20)
Moro (p. 128): Replace the Wound Penalties as follows: Infant Form: –1 (1–3), –3 (4–6), –5 (7–9), Incapacitated (10–12); Insect Form: –1 (1), –3 (2), –5, (3), Incapacitated (4)
Common White Wolves (p. 129): Replace the Wound Penalties as follows: –1 (1–6), –3 (7–12), –5 (13–18), Incapacitated (19–24)
Shadow Owls and Fire Hawks (p. 130): Replace the Wound Penalties as follows: –1 (1–2), –3 (3–4), –5 (5–6), Incapacitated (7–8)
Fire Hawks (p. 130): Replace all the references to "fire kites" with "fire hawks".
A Window of Singular Direction (p. 141): Change the Target to Part, add "+1 Part" to the calculation, and increase the level to 15. This is then not wrong as it stands, but can only affect dirt walls. Increasing the Base to 4, and the spell level to 20, creates a version that can affect stone walls, which fits the descriptive text better.
Timeline (p. 144): Change the date of the 1010 entry to 1011.
Realms of Power: The Divine, Revised Edition
Map (p. 10): Change the Graveyard legend to say Dominion 3.
The Fifth Ring of Solomon (p. 100): Replace the paragraph immediately before the formula with "This power works on beings or creatures that either belong to a realm or are aligned to a realm. To determine to which realm as creature is attached, roll as described below. You do not need to Penetrate Magic Resistance."
Flaws (p. 135): Replace the introductory paragraph with "Non-magi Jewish characters typically take a form of the Outsider Flaw, either the existing Major Flaw for companions, or the new Minor version for grogs. These Outsider Flaws are compatible with other Jewish Social Status Virtues and Flaws, but not with the Hermetic Magus Social Status Virtue."
Outsider (p. 136): Replace the second paragraph with "This Flaw is usually only appropriate for grogs; companions should take the Major Flaw instead."
Houses of Hermes: Mystery Cults
Statistics of Shapechangers (p. 23): Change Per –1 to Per +1 in the statistics for Ulf in Heartbeast form.
Acquiring Powers (p. 33): In the example, at the top of the third column, replace "Rego Corpus Lab Total" with "Rego Animal Lab Total".
The Magic of House Bjornaer (p. 35): In the penultimate paragraph of the page, replace "Speak with the Living Flame" with "Words of the Flickering Flame".
Common Virtues & Flaws (p. 37): Delete "Bad Reputation" and its note. The Flaw does not exist in ArM5.
Animal Creation Example (p. 43): Add "Fast Runner" to the list of Qualities the storyguide picks (in the second paragraph).
The Avenue of Befriending the Silent and the Station that Charms the Elements (p. 67): Change to "Target Level 18, as Major Virtue 21 (speak to elementally-pure objects), -3 third Initiation since a Major Ordeal".
The Avenue that Splinters and the Station of Blood and Bronze (p. 68): Change "Attack Bonus" to "Attack Total" in the final paragraph.
Inoffensive to (Beings) (p. 86): Change the category to "Minor, General and Hermetic".
Vim (p. 95): Add the following sentences immediately before the last sentence of the paragraph. "Muto Vim animae spells turn existing spells into faeries. Unlike standard Hermetic MuVi spells, they do not modify a spell as it is being cast."
Nature Lore (Minor Outer Mystery) (p. 103): Change the last sentence of the first paragraph to read as follows. "Merinita's interest was reputedly Forests, and thus that is the most common version. Forest Lore, as described in Guardians of the Forests: The Rhine Tribunal, is a closely related ability, but is not Supernatural, and thus does not require Initiation."
Reforging Enchanted Items (Minor House Mystery) (p. 125): In the first paragraph of the second column, replace "higher than" with "equal to or higher than".
Repairing Enchanted Items (p. 125): In the penultimate paragraph of the page, replace "higher than" with "equal to or higher than".
Expanded Form and Material Bonuses (p. 137): Delete "Alexandrite" under "Minerals". It wasn't discovered until 1830, and thus arguably does not exist in Mythic Europe.
The Scribe's Touch (p. 96): Change the Arts to ReAn.
Ring and Circle Ward Examples (p. 104): Change the level of Ward Against the Curious Scullion to 30, and replace the calculation with (Base 15, +1 Touch, +2 Ring). Change the level of Ward Against Mundane Intrusions to 50, and change the level calculation to read "(As Ward Against the Curious Scullion, +4 requisites)".
Highly Organized (p. 116): Replace the third sentence with "A season of such work (with the normal chances of changes to laboratory Virtues and Flaws) may still be undertaken, even if no improvement to Refinement is possible."
Realms of Power: Infernal
Early Punishment for the Sinful Witch (p. 122): Change to Pe(Mu)Vi(Ig). Change the effect level description to "…has a level equal to or lower than half this spell's…"
City and Guild
Superior Items (p. 69): After the second sentence of the paragraph, add the following sentence. "Only one bonus from a superior or excellent quality item applies to a single total or roll, no matter how many such items are used." In the antepenultimate sentence of the section, replace "rolls" with "rolls or totals".
Excellent Quality Items (p. 69-70): Before the sentence before the formula, add the following sentence. "As with superior items, only one bonus from a superior or excellent item applies to a single roll or total." On page 70, replace "rolls to make a book" with "totals to make a book".
Potion of Creation (p. 56): In the description, change to "if a stress roll plus her Stamina succeeds against an Ease Factor of 9."
Araquiel's Legacy (p. 67): Replace "Herbam" with "Terram".
Apollo's Luminescent Blessing (p. 110): Add "+3 uses/day" to the calculation. The final level is still correct.
Demeter's Blessing (p. 111): Change the calculation to (Base 1, +1 Touch, +4 Year, +4 Bound, +1 Size [for a total of +4 Size]). The final level is still correct.
Opening the Hidden Eyes (p. 111): Change the calculation and levels as follows. (Base 5, +1 Conc, +4 Vision, +2 extra detail); Ease Factor: 14; Level Cost: 40
Hermetic Rune Magic (pp. 139-140): In the middle of the central column on page 140, after the mention of Opening the Intangible Tunnel, add the following sentence. "The Intangible Tunnel has the same level as the runic effect."
Houses of Hermes: Societates
Test of the Flames (p. 36): Change T:Circle to T:Ind.
Last Flight of the Phoenix (p. 37): Change R: Per to R: Touch, change the damage to +40, and the calculation to (Base 35, +1 Touch, +2 size)
Art & Academe
Pieces of Art as Advancement Sources (p. 126): Change "Art Advancement Total" to "Source Quality". Add the following sentence at the end of the second paragraph. "It takes one season to study a single work of art, and each work of art may only be studied once, like a tractatus."
Realms of Power: Magic
Falcon (p. 142): Change Com to –2.
Realms of Power: Faerie
What Do Size Scores Represent (p. 49): The first Size entry should be –11, not –1.
Creativity (p. 65): Add the following sentence at the end of the first paragraph. "All necessary rolls are made using whichever Ability is appropriate for the form of creativity being employed, such as Music or some variety of Craft."
Faerie Sympathy (p. 112): Change the third sentence of the first paragraph to read "This Trait may be increased with experience points, up to a maximum of the character's Warping Score". Add the following sentence to the second paragraph. "Characters with the Minor Virtue must have a Warping Score of at least 1, and those with the Major Virtue must have a Warping Score of at least 3."
Faerie Antipathy (p. 114): Delete the sentence about subtracting the character's Warping Score from the value.
Tales of Mythic Europe
Faerie Speech (p. 6): Replace the text with the following. "Faerie Speech allows faeries to converse in the language of their audience. They can speak any language that someone has used to speak to them, and this effect does not need to Penetrate because it only affects the faerie."
Chirurgeon's Healing Touch (p. 54): Replace "Fast Casting" with "Multiple Casting" in the list of mastery abilities.
Carnivorous House (p. 55): Change the level to 40, and add "+1 Touch" to the calculation.
Magi of Hermes
Asp (p. 9): Delete "Powers" above "Venomous Bite", add an asterisk before "Venomous Bite", and remove the point cost and Init value.
Crocodile (p. 10): Rename the "Powers" section to "New Qualities", changing "Death Roll" to "Roll Attack", and deleting the point cost.
Mold the Earth Within Sight (p. 40): Change the level to 25, and in the analysis change "+2 stone" to "+1 stone".
Circle of Undisturbed Rest (p. 30): Change the Arts to PeIm, with a Rego requisite, change the level to 25, and change the calculation to (Base 4, +1 Touch, +2 Ring, +1 Rego (species are destroyed at the Ring rather than the source), +1 changing image).
Petalichus of Verditus (p. 96): Change "Verditus" to "Verditius" in the chapter header, and "Veriditus" to "Verditius" in the first line of the first paragraph.
The Patient Spell (p. 113): Change the second sentence to "The target spell can be no higher than the level+15 of The Patient Spell.".
Image of the Lady (p. 124): Change the Target to Individual.
Lords of Men
Gyrfalcon (p. 59): Change Com to –2.
Stables [Table] (p. 60): Move all the numbers in the "Excellent (Great Noble)" line one space to the right.
The Cradle and the Crescent
New and Modified Flaws (p. 80): Change the introductory sentence to read "These Flaws are designed for Faerie jinn characters." It is Atlas policy to preserve the privacy of all contributors, and not comment in print on whether they may or may not be Faerie jinn.
Transforming Mythic Europe
Woolen Steed of Araby (p. 111): Increase the level to 20, and change to "+2 for increased speed" in the calculation.
Vessel of the Clouds (p. 112): Increase the level to 35, and change to "+2 for increased speed" in the calculation.
Faith and Flame
Feminine Sympathy (p. 29): Change the sentence beginning "All rolls…" to "All rolls using this Trait must use stress dice". That is, delete the reference to the rolls becoming faerie powers.
Through the Aegis
Lexora of House Bjornaer (p. 43): Change Aegis of the Hearth to level 20. (Ritual spells cannot be lower than level 20.)
Lands of the Nile
Hippopotamus (p. 18): Add "Overrun" to Qualities. Rename the "Powers" section to "New Qualities" and delete (non-magical).
Crocodile (p. 19): Add "Roll Attack" to Qualities. Rename the "Powers" section to "New Qualities", changing "Death Roll" to "Roll Attack", and deleting (non-magical).
Elephant (p. 20): Change Cun to +1, and Com to -5/-4*. Add Overrun and Trunk to Qualities (in alphabetical order), and rename the "Powers" section to "New Qualities", deleting "(non-magical)" in each case.
Baboon (p. 22): Change Com to 0/+1*, and Pre to –2. Change Combat to: Bite Init +2, Attack +11, Defense +9, Damage –3, Evasion Init +2, Attack n/a, Defense +9, Damage n/a. Change Mundane Qualities to Aggressive, Ambush Predator, Crafty, Pack Animal/Pack Leader, Skilled Climber, Vocal. Change Abilities to Athletics 3 (climbing), Awareness 3 (food), Brawl 5 (bite), Hunt 4 (prey), Stealth 4 (stalking prey), Survival 3 (savannah).
Elephant-Eating Serpent (p. 23): Add Constriction and Swallow Whole to Qualities. Rename the "Powers" section to "New Qualities" and delete (non-magical).
Scorpion Fish (p. 23): Add Swallow Whole to Qualities. Rename the "Powers" section to "New Qualities" and delete (non-magical).
The Seekers' Guild (p. 24): Change "Al-Majalibeen" to "Al-Matalibeen" in the title.
Initiation Script for the Rank of Temple Priest (p. 100): Towards the end of the first paragraph, change to "and she will not necessarily become bedridden and die of old age at a Decrepitude of 5."