Error: Failed to connect to database. An underlying database error occurred. Could not start session

Error Message

When trying to access many personal geodatabases (pGDB) (e.g., more than 126 unique pGDBs) in ArcMap or ArcCatalog, the following error message is displayed:

"Failed to connect to database.
An underlying database error occurred. Could not start session."

Cause

This is a limitation of the Microsoft Jet Engine. See the link in the Related Information section for more information.

Solution or Workaround

Convert the data to file geodatabases.

    Related Information