The following are the symptoms of the QuickBooks Won't Open issue. The program becomes unresponsive. The corporate file for QuickBooks does not open. Windows slows down. Occasionally, the computer may hang. The computer is sluggish to react to mouse and keyboard inputs. The following are the causes behind won’t open error. The name of the firm must be somewhat lengthy. A hard drive has been corrupted. QuickBooks Desktop was installed incorrectly. The QBWUSER.INI file is missing or corrupted. The OS has become outdated.