Informix Error -851: Cannot drop file (check file permissions).

Reasons / Common Causes

-851 fires when a file-drop request fails — per the official guidance, probably a write- permission problem on the file itself or on the directory that holds it (removing a file requires write permission on its containing directory, not just the file).

1. No write permission on the containing directory, per the official guidance — since removing a directory entry requires directory-level write access, not just file-level.
2. No write permission on the file itself, in environments/tools where that also factors in.

Solutions / Resolution

1. Use operating-system commands to check the file permissions, per the official guidance:

   ls -l the_file
   ls -ld "$(dirname the_file)"
   

2. Correct permissions on the file and/or its containing directory, as needed.

Examples

Checking both the file and its directory

$ ls -l the_file
$ ls -ld "$(dirname the_file)"

Diagnostic Checks

1. Check both the file's own permissions and its containing directory's permissions — removing a file needs write access to the directory specifically.

Related Errors / Related Topics

• -816 — "Cannot write file (check file permissions)." A related file-permission error, for writing to a file rather than dropping/removing it.
• -817 — "Cannot read file (check file permissions)." A related file-permission error, for reading rather than dropping.

Check the containing directory's write permission, not just the file's own — removing a file needs directory-level access.