SymptomsEvery website uses MS Access ODBC connection isn’t loaded and fails after some timeout.
CauseJet creates a temporary file when the engine is started. In doing so, it first checks the TMP environment variable and uses that path to define where the temporary file is created. If it doesn't see a TMP environment variable, it looks for the TEMP environment variable.
If TEMP is not defined, it then uses the Windows folder .
If TMP/TEMP is defined but points to a nonexistent folder, the error occurs.
Moreover, when opening the Access database through IIS or a Windows service, and when IIS or the service is running under the local system account, the TMP or TEMP system environment variable is used. When the Web services is started using a user account, the TMP/TEMP user profile environment variables is used.