Spell Checking on a 68000 Macintosh (Classic, SE or Mac Plus) will cause ClarisImpact 1.0v1 to crash with this message, "Sorry, a System Error occurred. File System Map inconsistent." Other messages are possible, such as "Unexpectedly Quit", etc.
If you have an accelerated 68000 Macintosh the crash will not occur when spell checking since the accelerator typically will be using a 68020, 68030 or 68040 processor to accelerate.
This is fixed in ClarisImpact 1.0v2. Contact Claris Customer Assistance at 408-727-8227 for an update.