Time Machine - Troubleshooting
C10. "Error: (-50) Creating directory"
or "error ... while creating the backup folder."
Time Machine - Troubleshooting
C10. "Error: (-50) Creating directory"
or "error ... while creating the backup folder."
This may indicate a problem with your backups. Repair them, per item #A5.
If no errors are found, or they're all found and fixed, but you still get the message, try a "full reset" per item #A4.
If neither of those helps, and Disk Utility shows no errors, try ejecting, disconnecting, and powering the Time Machine disk off for several minutes. Restart your Mac, then reconnect and power up the disk.
It's also possible there's a problem with a port or cable. Make sure all connections are snug and secure. Try different port(s), cables, and combinations of the two (a plug that works fine in one port may not make good, consistent contact in a different one).
If this continues, or happens again, see if your backup drive has the GUID or Apple Partition Map Partition Map Scheme. In the Disk Utility sidebar, click the top line for the drive (with the make and size); the Partition Map Scheme will be shown at the lower-right. If it's Master Boot Record, Time Machine may not work well. You'll have to erase and reformat it, per #1 in Using Disk Utility.