If QuickBooks won’t open company file then you need to see if you are using the latest version of QuickBooks or not. For that, you should visit the official website and download the most recent update. If you already have the latest version then try to rename the TLG and ND files for your company files and then open it. You can do it in the below mentioned ways: · Open the file explorer and then search for the folder where you have saved the company file. · Search for the TLG and ND files that have the same name as your company file. · Right click on any of them and rename. · Once you are through with it, open the QuickBooks and your company file too.