The application has unexpectedly quit
Apple Classic Macintosh
Severity: ModerateWhat Does This Error Mean?
This message means an application crashed but the system itself survived. Unlike the bomb dialog, the Finder caught the crash and can continue running. You may have lost unsaved work in that application, but other open applications are usually unaffected.
Affected Models
- Macintosh Plus
- Macintosh SE
- Macintosh Classic
- Macintosh II
- Macintosh LC
- Macintosh Quadra
- Power Macintosh
- Basilisk II emulator
Common Causes
- Application bug — bad memory access or logic error
- Insufficient memory allocated to the application
- Extension conflict interfering with the application
- Corrupted application or preference file
- Trying to open a file that is too large for available memory
How to Fix It
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Increase the application's memory allocation.
Click the application icon once, choose Get Info (Command-I). Increase the Preferred Size under Memory Requirements by 50%. Classic Mac OS gives each app a fixed memory block — too small causes crashes.
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Delete the application's preferences file and try again.
Look in System Folder > Preferences for a file named after the application. Move it to the Trash and relaunch the app — it will create fresh preferences.
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Restart with extensions disabled (hold Shift at startup) and try the app again.
If the app works with extensions off, an extension conflict is the cause. Re-enable extensions one at a time to find the culprit.
-
Reinstall the application from the original discs.
The application file itself may be damaged. Reinstalling replaces all files with known good copies.
Frequently Asked Questions
Why does Classic Mac OS not have protected memory?
Classic Mac OS (System 1 through 9) was designed for single-tasking and later cooperative multitasking. Applications share the same memory space — one bad app can corrupt another's memory. Mac OS X introduced true protected memory in 2001.
What is the difference between this message and the bomb dialog?
This message means only the application crashed — the system is still running. The bomb dialog means the system itself crashed and needs a restart.