Symptom
A script using FileMove works in development, but in staging ioerrtext returns No such process.
The source file exists, the destination directory was created successfully, and the surrounding logic (Exist, MkDir, path checks) is demonstrably correct.
The only visible difference is that staging uses a longer network or share path than development.
Cause
The error text is misleading: no process is missing.
In the diagnosed case the source and destination paths were valid, but the assembled destination filename was too long for the staging filesystem path.
The failure surfaces at the file operation boundary, so every check before the FileMove call passes and the error appears to come out of nowhere.
This is worth internalizing as a pattern: low-level file functions report OS error codes through ioerrtext, and the mapped text often describes the errno, not your actual situation.
Fix
Before the FileMove call, log the complete source path, destination directory, destination filename, and the numeric return code.
Compare total path length and filename length between the working and failing environment.
Then shorten what you control: generated identifiers in the filename, nested directory names, or the backup root itself, while keeping the name unique.
Two safety rules for the surrounding script:
- Keep collision handling that deletes an existing destination file, but never delete the source until the move has been confirmed successful.
- If you cannot see the path the runtime actually assembled, raise the log level temporarily (level 4 in this lineage) instead of guessing.
Also rule out the neighbors: verify the service account can reach the network share, because a permissions or antivirus failure produces a different filesystem error with the same surrounding symptoms.
Budget for the full production path
Development paths are usually shorter than production paths, which accumulate share names, environment prefixes, and archive date folders. Any filename you generate by concatenation deserves a length budget checked against the longest target path it will ever meet.