First job out of college. Homemade crypto plugin for SQL Server sometimes corrupted client data, which was life & death important. Couldn't recompile the plugin

First job out of college. Homemade crypto plugin for SQL Server sometimes corrupted client data, which was life & death important. Couldn't recompile the plugin. Discovered race condition causing use of fallback crypto key. Taught tech support to decrypt with fallback key. Looked through compiled machine code. Discovered race condition triggered by particular two-byte opcode sequence that happened to be readable ASCII and unique. Taught tech support to search and replace that opcode sequence with Notepad++ in the DLL, changing a comma to a tilde, thus solving the problem once and for all.