unable to install the update

Update your WinRAR or use 7-zip. The latter is recommended since G4TW releases are now in .7z format.

I'm having this issue as well, specifically with the TS4.exe in the bin folder. I only play TS4 in 32bit, and suddenly I'm getting the same error as misterfenty. I used both winrar in administrator mode, and in 7zip. Same issue. Hoping to get some help as the game lags too much to enjoy in 64bit.

Download the update again then. Because extracting it with up-to-date 7-zip works fine.

Or - when you are familiar with iso's - download these updates in .iso format HERE

Tried both downloading again, direct and with torrent, and mounting in .iso format. Same issue with the same file. No other issues. I have no idea what is causing this..

Try update 1.48.94.1020 and make sure the download is completed and shows seeding or uploading.
https://www.games4theworld.club/t34601-the-sims-4-update-1-48-94-1020-out-now#

That's the update I was talking about. It's after this new update that this issue started. No access to that one specific file (TS4.exe in bin, TS4_64.exe has no issues)

I've torrented patches before and had no issues. I really have no idea what's going on with this. It's as if the permissions for that one singular file are screwy. Any ideas? Since it definitely doesn't seem to be related to the actual download from what I can tell. (Obviously I may be wrong-- just want to find a way to fix it, and being wrong is good if it means I can play again!)

UPDATE:

I think I found a fix, and it was stupidly simple when I thought about it.

For some reason, the game/bin thread weren't in my antivirus exception list. Now I know they were there before, so I have no idea. But specifically TS4.exe flagged as a virus and was quarantined. Restored it and I can update it properly now!

Definitely should have double checked that, sorry for the trouble!

Misterfenty, I would definitely check to see if the Sims 4 folder is part of your exceptions list in your antivirus, since that may be what's interfering with the permissions.