| Ol | Bus error | Macintosh malfunction |
| 02 | Address error | Application error or software incompatibility |
| 03 | Illegal instruction | Application error or software incompatibility |
| 04 | Divide by zero | Application error |
| 05 | Check exception | Application error |
| 06 | Trapv exception | Application error or software incompatibility |
| 07 | Privilege violation | Application error or software incompatibility |
| 08 | Trace exception | Trouble occurred with programming tools or an unusual hardware accessory |
| 09 | Line 1010 exception | Application error |
| 10 | Line 1111 exception | Application error |
| 11 | Miscellaneous exception | Application error or software incompatibility |
| 12 | Unimplemented core routine | Application error or software incompatibility |
| 13 | Spurious interrupt | Interrupt part of programmer's switch was pressed, or trouble occurred with programming tools or an unusual hardware accessory |
| 14 | I/O system error | Trouble occurred with programming tools or an unusual hardware accessory |
| 15 | Segment loader error | The System file is probably corrupted |
| 16 | Floating-point error | The System file is probably corrupted |
| 17-24 | Can't load package | The System file is probably corrupted |
| 25 | Memory full | The application suddenly ran out of memory |
| 26 | Segment loader error | Trouble opening an application, or the System file is corrupted |
| 27 | File map destroyed | The System file is probably corrupted |
| 28 | Stack overflow error | The application suddenly ran out of memory |
| 29 | AppleShare error | Problem with AppleShare file server |
