PVSS00data - SYS/SEVERE - doBackupStart, Could not open input file for backup, backup aborted

Enclosed you'll find the explanation for a log-message which occurs when an error at the online-backup is noticed.

Log-message with symbolic names:

PVSS00data (0), <TIMESTAMP, SYS, SEVERE, 54, Unexpected state, DataManDpInternSup, doBackupStart, Could not open input file for backup, backup aborted

This log-messages describes that the input-file for the backup-functionality could not be created/written.
Please check if the "data" directory exists at your WinCC OA-project.
If the directory is not existing please create it and ensure that the operating-system user which is starting the project has write access to this directory.

Also please check if the directory does not contain write-protected files with the names TEMPFILE_IN and TEMPFILE_OUT.
If those files are write-protected please grant full access for the operating-system user starting the project.