TWRP createTarFork() error 255 when backing up data

I think I found the solution!

1. In TWRP, go to "Wipe" and swipe to factory reset


2. Download:
   
   
   
   
   • OnePlus Recovery: oxygenos.oneplus.net.s3.amazonaws.com/OP5_recovery.img
   
   
   • OxygenOS: oxygenos.oneplus.net.s3.amazonaws.com/OnePlus5Oxygen_23_OTA_015_all_1708252353_e6d7756780064352.zip
   
   



3. Rename the recovery image as recovery.img, boot phone into fastboot, plug into the computer, run these commands on the computer:

   
   
   

   fastboot devices
   
   fastboot flash recovery recovery.img
   
   fastboot boot recovery.img
   
   




4. Open recovery on the phone



5. Select "Forgot Password", this will wipe all leftover files in SD Card.


6. Boot back into recovery, select reload, select "Install over ADB" or "Install Over USB" or something similar and plug the phone into the computer.


7. Run adb sideload oxygen-os-filename on the computer.


8. Let it install OxygenOS, it may appear to be frozen at some points; it probably isn't, so don't shut it off or unplug USB.


9. Download Bluspark TWRP



10. Reboot into fastboot, plug into the computer and run these commands on the computer:

    
    
    

    fastboot devices
    
    fastboot flash recovery bluspark-twrp-filename-location.img
    
    fastboot boot bluspark-twrp-filename-location.img
    
    




11. Success (hopefully)