I have been trying for over a week to DL the PTS. Had downloaded it several times earlier, now it gives me the following:

Installing Main Assets 301 (0%)

I let it go the other day for over 30 minutes. Didn't budge. Repeated attempts yielded nothing.

Edit: And the only way to close the launcher at that point was via task manager.

Hallelujah, finally got the PTS download to work.

Deleted everything in

C:\Program Files (x86)\Electronic Arts\BioWare\Star Wars - The Old Republic

and its subfolders where anything said "test", including manifests, asset files, etc.

Re-downloaded the SWTOR_setup.exe, had it verify the main game, went into its settings and set it to enable the PTS again, relaunched it, flipped to the test environment. Done.

Previously deleting the bitraider folder was useless. I think there was an issue where somehow the launcher was seeing an old test manifest file and getting hung up somehow. I couldn't even kill the launcher without going into task manager, but at least the above trick worked.

Yay me.