Let's repair QuickBooks, ____. This fixes program-related issues.

Before doing the process, create a backup copy of your company file to avoid data loss. 

Here's how to repair QuickBooks:

1. Click the Windows icon, then go to Control Panel (In Windows 8/8.1: From the Start menu, open Search and type Control Panel. From the results, select Control Panel.)
2. Select Programs and Features.
3. Select QuickBooks, then click Uninstall/Change.
4. Click Continue, then Next.
5. Select Repair, then click Next.
6. Wait for the repair to complete, then click Finish.
7. Restart computer when prompted.

Once done, try to search for vendors and customers, and check if you're able to do so without any issues.

Get back to this thread if something comes up. We'd be happy to help you again.