Mistakes happen, and sometimes players come up with situations the BattleTech designers, writers and testers never imagined. If you believe you’ve found a problem, report it in the appropriate thread on our forum.  Catalyst rolls in all approved errata every time a product is reprinted.

Below is all official errata issued for our products. Some of the errata below is for a specific printing of a book.  To determine what printing you have, check the last page of the credits section.  If it’s any printing past the first, this will be noted on that page (e.g. “Corrected Fifth Printing”).

Errata last updated 1 September 2020.




A Game of Armored Combat Errata version 4.01

This PDF is 319KB.


BattleMech Manual Errata version 3.21

This PDF is 406KB.
In addition, there is one other download for the BattleMech Manual. This corrects the 1st printing’s flawed flowchart on page 42:

BattleMech Manual Corrected Damage Flowchart p. 42


Total Warfare Errata version 6.1

Total Warfare 5th Printing

This PDF is 655KB.

TechManual Errata version 4.0 – General Changes

This PDF is 808KB.

In addition, there are two other downloads for TechManual. The first replaces pages 302-314 as well as page 319, the second replaces pages 349-352. Both are featured in the most recent TechManual releases, but are released here separately for your convenience.

TechManual Errata version 4.0 – Battle Value (Dec 2019)
TechManual Errata version 3.0 – Infantry Weapon Tables (Dec 2017)


Tactical Operations Errata version 3.03

This errata is for the single-volume version only.
In addition, there is one other download for Tactical Operations, for all printings, which adds landing modifiers for the various types of special terrain found in that book:

Tactical Operations Landing Modifiers


Strategic Operations Errata version 3.02

This PDF is 476KB.
In addition, there are two other downloads for Strategic Operations. The first replaces the Customization rules found on pp. 188-189, while the second updates the BattleForce rules to take advantage of some of the rule changes brought about in Alpha Strike.

Strategic Operations Revised Refitting v3
Strategic Operations BattleForce Update v1.3


Interstellar Operations Errata version 1.1

This PDF is 296KB.

A Time of War Errata version 2.02

This PDF is 158KB.


Alpha Strike Commander’s Edition Errata version 2.0

This PDF is 322KB.


Alpha Strike Errata version 2.5

This PDF is 625KB.


Alpha Strike Companion Errata version 1.3

This PDF is 477KB.

In addition, there is one other download for the Companion, which clarifies the heat conversion process:

Alpha Strike Companion Converting Heat Errata version 1.2


TRO Clan Invasion Errata version 2.0

This PDF is 253KB.