How do I delete the incomplete update files

@Rapunzel_Fitzh  Please hit Windows key-R and enter %ProgramData% in the run box that appears.  Open the EA Desktop folder, right-click on each of the folders inside, select Properties, and look for any folder that's more than a trivial size.  For comparison, on a computer with only Sims 3 and 4 installed, my EA Desktop folder has five entries, and the entire folder is less than 5 MB in size.

You can also check the sizes of the Electronic Arts and Origin folders inside ProgramData; mine are less than 1 MB each.  The idea here is not to delete everything—in fact, that may be detrimental in unpredictable ways–but to find the one folder that's much larger than it should be, then dig until you find the subfolder or file that you need to delete.

Hit Windows key-R again and enter %AppData%.  You'll land inside the Roaming folder, but that's not what you need.  In the address bar, click AppData instead, then open the Local folder.  Check the sizes of the EADesktop, EALaunchHelper, Electronic Arts, and Origin folders.  If you find something excessively large inside one of them, that's what you need to delete.  Mine range from less than 1 MB to 30 MB.

If this doesn't help, you'll need to brute-force it.  Click This PC in the left panel of the File Explorer window, then double-click the C drive.  Check the size of each of the folders inside.  Some will be large, for example the Program Files folder; the idea here is to figure out what's too large for its purpose.  If you don't see anything obvious, click View near the top of the window, then check the box next to Hidden Items, which will show normally-hidden files and folders.

You can open the folders and look for anything you don't recognize that's large enough to account for the excess data, but before deleting anything, please list what you've found and ask.  Some of these folders have cryptic names but are absolutely essential, and deleting one of them could brick your computer.