When I synthesize a design in Project Navigator, XST reports the following error message:
"ERROR:HDLParsers:3220 - File not found: xst/work/sub00/vhpl31.vho"
However, the design completes synthesis and it is possible to continue with implementation.
This error can occur when Project Navigator is used; older projects might have corrupted compiled files.
You can avoid this issue by cleaning up the project files in Project Navigator as follows:
Run Project -> Cleanup Project Files.
Rerun synthesis, and the error should disappear.