Problem borrowing ArcMap 10.0 license from 10.1 lic. manager

Discussion created by tmkantol on Aug 26, 2012
Latest reply on Mar 1, 2013 by mvolz47
We recently upgraded our ArcGIS license server to 10.1

After, we received complaints from a client (using the server) that borrowing ArcMap 10.0 license no longer works.
Or, more precisely, he wrote that borrowing seems to work, but starting ArcMap after borrowing gets stuck with message "Initializing license..." - i.e. ArcMap won't start, and also returning the license won't succeed.

The client had tried with 3 different computers, two of them had ArcGIS 10.0 service pack installed.
I am using desktop 10.1, and borrowing works fine for me - returning the license does not succeed, however.

We were told by ESRI, that 10.1 license manager should be backwards compatible with 10.0

Does anyone have a clue of what might be the problem? Something went wrong with license manager installation? Or some compatibility problem? Or something else that should be noted?
Does anyone else experience the same?

Our local ESRI customer service was not able to help.