June 2019
@1_Apocryphal_1 It should be fine, but it might still try to patch TS3 and take over. Watch it carefully when you open it and cancel any updates. (It's not always clear whose games get auto-patched, although disc installs seem less vulnerable than digital ones that predate patch 1.69.) Be sure to disable auto updates in general; it'll be one of the options checked on the menu you see the first time you open Origin. (You might want to turn off all the options, just because otherwise Origin can be pretty invasive.) Besides, it's easy enough to manually update a game when you want to play.
June 2019
Thank you so much, you're awesome!