Print Spooler is preventing hibernation or standby

All of a sudden I began getting the following message

The service 'Print Spooler' is preventing the machine from entering hibernation. Try stopping this service and try again

This also applies to

The service 'Print Spooler' is preventing the machine from entering standby. Try stopping this service and try again

First I stopped the print spooler service

Then I went to the C:\WINDOWS\System32\spool\PRINTERS folder and deleted all files in there.

Then I restarted the print spooler service.