Hello,
Environment is Windows Server 2016, postgresql 12.3, pg_probackup 2.4.1.

My scheduled base backups had been running smoothly for 6+ months, then recently have been getting the following error:

2021年07月30日 20:35:16 Eastern Daylight Time [4240]: INFO: Syncing backup files to disk
2021年07月30日 20:35:18 Eastern Daylight Time [4240]: ERROR: Cannot sync file "L:/pg_probackup/backups/carrp/QX2VS1/database/base/1260964/1263666.12": Permission denied
2021年07月30日 20:35:18 Eastern Daylight Time [4240]: WARNING: Backup QX2VS1 is running, setting its status to ERROR

Full log is attached.

The backup command is run under windows task scheduler with our Domain Admin credentials.

pg_probackup.log