The schema filter files are not created if the schema name has a backslash (\).
As an example, let's say that the schema name is "Mountain\Bike". When users exit out of TOAD, a filter file (.FLT) is created with the name of the schema. So in theory, the file: "Mount an\Bike.flt" should be created. However, when TOAD tries to create this file, this error occurs: "Cannot create file "C:\Program Files\Quest Software\Toad for Oracle\User Files\Mountain\Bike.FLT. The system cannot find the path specified."
NOTE: This problem does not exist in TOAD 7.4. In TOAD 7.4, TOAD creates a new subdirectory in the Temps folder. So this file is created: C:\Program Files\Quest Software\Toad\Temps\Mountain\Bike\Bike.FLT.