No mods and lunching problem after update.
cattwood3 Which problems still exist with your Mods folder removed?
The alt-tab issue is a problem with the (now default) DirectX 11 version of Sims 4. You can get around it by playing in windowed mode, or by switching back to DirectX 9. For the latter, if you can reach the Main Menu and open the Options menu, DX9 is an option with the other graphics settings. If you can't, open the EA App, click Sims 4 > Manage > View properties, and add -dx9 in the command line box.
Switching to DX9 may fix the graphical glitches as well; please do test with no mods or custom content present. Regardless of whether this helps, please provide a dxdiag. Hit Windows key-R, enter dxdiag in the run box, wait for the scan to finish, click "Save all information," and save the file to your desktop. From there, you can attach it to a reply using the camera (Insert Media) icon included with the other formatting buttons.
