Incorrect permissions, a corrupted QuickBooks installation, network problems, or file corruption could be the cause of your inability to open your QuickBooks company file. Verify the file extension, make sure the file is not in use, then utilize QuickBooks File Doctor to correct any issues. Verifying folder permissions and updating QuickBooks can also assist in fixing the problem.If you experience any problems, call the QB support team at 1.855.738.2784.