• A round icon shows how many unique bugs are stored. A red count is unseen. Left click opens the window and turns the count green. Right click clears the red alert and leaves the list in place. • The window shows one bug at a time: addon, filter, repeat count, first and last time, active window, mouse window, zone, and career. An addon list filters the view. Previous and Next walk the list. • Copy selects the current bug. Copy all selects the bugs in the current filter. Ctrl+C copies the selection. The game has no addon call that writes the clipboard. • Clear removes the list for this session. After /reloadui, Error Sack reads the UI log again, so press Clear after that reload. • Errors and warnings from the UI log are collected, and so are explicit Lua error() calls. The same message raises its count instead of adding another row. • The list holds 100 unique bugs. If errors arrive in a burst, capture pauses and then resumes on its own. • The Lua debug library is requested so the next reload can attach a stack to error() calls. • Four ordinary client lines stay out: UrlStrings already in use, missing font 2002L_NHN.ttf, missing texture GOA.dds, and missing MythicApprovedMods.txt. Layout-editor warnings about cut-off text, auto-scaled fonts, and windows that are not handling input stay out as well. • Commands are /errorsack, /errors, and /bugsack. test, next, prev, copy, all, and clear work after the command. /errorsack test adds one sample line.