Problem:

The ACUCOBOL-GT application is accessing the runtime over a mapped drive. If the program is left running idle for approximately 30 minutes, when the user tries to reactivate it again the runtime would crash. In the Process Mononitor log, a network error was tracked with reference to the runtime.

Resolution:

The first advice in cases like this is to avoid the use of mapped shared drives.

If it's impossible to spare this architecture, some registry settings may improve the situation.
(see other articles in the Extend and ACUCOBOL Community about Opportunistic Lock)

If the Operating System is Windows 10, users should be aware that Microsoft has added additional security to using mapped drives.

Doing some researches, it's easy to find articles like the following which may explain the situation and implement a solution:

Windows 10 losing mapped drives
http://bit.ly/2fQyS6a

"It appears this issue has actually been around since Windows 8 and is caused by Group Policy drives which are set to "Recreate". Windows 8/10 automatically runs Group Policy updates in the background and disconnects/reconnects the drive to Recreate it.

Change the drive to "Update" in group policy and the issue will disappear!"

This fixed the network error problem.

SI: 2879302