Thank you for posting in the Final Fantasy XIV Technical Support Forums.

Have you had issues with DirectX crashes in the past? Also, before Patch 4.5 was downloaded were any changed made to the PC? Also have you tried changing the compatibility mode? If not, please try the following:

To change compatibility mode, right click on the exe file (Default location: C:\Program Files (x86)\SquareEnix\Final Fantasy XIV - A Realm Reborn\boot\ffxivboot.exe), right click it and select ‘Properties.’ Select the ‘Compatibility’ tab and select Windows 7.

Hope to see you online!