Microsoft veteran Raymond Chen recounted a crash in Word 97 that appeared only during testing and vanished when a debugger was used. The issue surfaced near the end of the Word 97 release cycle, when a script could reliably trigger the crash in lab tests. Developers were unable to reproduce the failure under debugging conditions, which made the defect challenging to locate. They traced the problem to a CPU manufacturing erratum and a specific instruction sequence. Recompiling the compiler would have risked new bugs, so the team applied a binary patch that inserted a NOP into the offending code. The patch was applied before the final release, allowing Word 97 to include Clippy and Visual Basic for Applications.