I haven't seen this but here are steps that I have found online in the swtor forums posted by others such as Owenbrooks. I take no credit for these steps but they are options to try.
Delete the DiskCacheArena file under the swtor directory.
If that doesn't work, you can also try running a repair:
Non-Streaming launcher - Log into the launcher but don't click Play. Check for small letters "ST" in the bottom left corner. If this is NOT present, click the cog icon and then run the repair option.
Streaming launcher - If the letters "ST" is present, close the launcher, right mouse click on the game shortcut, select open file location and delete the BitRaider folder. Then start the launcher.
Worse case scenario switch to the non streaming launcher:
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.
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“PATIENCE YOU MUST HAVE my young padawan”
– Yoda
Server: Satele Shan
Volunteer forum moderator, I do not work for EA / BW.