Here you can configure if the button "Clean up back files" is hidden in Presentations's File | Options dialog box.
Registry Hive | HKEY_LOCAL_MACHINE or HKEY_CURRENT_USER |
Registry Path | SOFTWARE\Policies\SoftMaker\Presentations 2018 |
Value Name | BackupNoCleanup |
Value Type | REG_DWORD |
Enabled Value | 1 |
Disabled Value | 0 |