So this small office (5 users) recently upgraded (from 2014) to QuickBooks Enterprise Solutions 15.0.
Apparently this has been a problem for the four networked users, but now the host as well will crash QB when changing "Active Customers" to "All Customers" and the Windows Error Reporting will give the Exception Code c0000005.
I've tried deleting the EntitlementDataStore.ecml file and renaming the QBWUSER.INI file (found these suggestions in the QB user community), but no change. Of course, I've done all Windows updates and rebooted, but no joy.
I tried the same operation with a sample file, and quickbooks did not crash then.