Unable to write patch due to insufficient disk space...

It's not a bug, it's just seeing that there is not enough space to download for some reason.  You can try to use Disk Cleanup to clear some space and see if it helps.  153gb seems like it would be enough however considering there are temp files while downloading it could be using more space then just what is patching.

Another thing you can do would be to go to into your swtor directory and see if you have a bitraider directory.  If you do you can switch to the non-bitraider version of the launcher and delete the bit raider folder which may help reduce the overall size of the game on your computer.

Steps to remove bitraider are below if you have it:

NOTE this is a complete download of the game again

right mouse click on game shortcut and select open file location

open the launcher.settings file in notepad and locate the below line and edit to the below

, "PatchingMode": "{ \"swtor\": \"SSN\" }"
, "bitraider_disable": true

SAVE the changes.
Delete the BitRaider, Movie and Asset folders then start the launcher.

If you don't have bit raider at all, I would use the Disk Cleanup above to see if it can help clear enough space to allow the download to complete

@Captainrover262

How much room is left on C drive ?

The C: Drive currently has 153 GB of space remaining out of 440 GB

Unfortunately none of the tips you recommended have worked, the same error continues to plague me. ☹️ I even tried deleting a few old games freeing up almost 20GB of space with still no sign of it succeeding.

@Captainrover262

Have you run a chkdsk on that drive ?

In the main game folder if a patch folder exists with the game closed delete it