If one directory configured in config setting "TempDirectories" is not available access to any database on the server is not possible with the following error:

> Unsuccessful execution caused by a system error that precludes
> successful execution of subsequent statements.
> I/O error for file "".
> Error while trying to open file.
> No such file or directory.

Firebird should use the next directory in that case and should behave the same way as if no free space on the disk would be available.