If you have an obfuscated database and attempt to run a Permissions Report, the following error appears:

Universal Time: (2019-09-18 13:39:48) Local Time: (2019-09-18 14:39:48) TimeZone: (01:00:00 DST)
Version: 5.2.0.15
EXCEPTION: InvalidOperationException

message: Cannot rename a sheet to the same name as existing sheet.
source: DevExpress.Spreadsheet.v16.2.Core
target: Void CheckValidName(System.String)

This is because each item in the Display dropdown has the same value.  As these values are used to name workbook sheets in the resulting spreadsheet, the process trips over Excel's requirement that each workbook sheet should have a unique name.

To fix this:

• Go to Admin > Segmentations > Permission Types
• Change each Permission Type value (the regular names are: Universe, Client, Entity, Audit)

You can now run the permissions report (close the Permissions tab if open already)