Allow your Android to access the Picture Keeper.
Picture Keeper needs permission from your phone to access the USB flash drive.
If a File Manager window opens, swipe to close, use the back arrow or recent tasks button to close.
Open the Picture Keeper app again.
Tap Start Backup.
You may get the same permission prompt.
Now tap PKBackup
Next tap Select at the bottom right or Select PK Backup. (depends on the phone)
This should now display the Start Backup screen.
Tap Allow or Deny to any prompts like Videos or Contacts.
Tap Start Backup
For further assistance, please contact Picture Keeper Support