Before doing anything to your partition table, it is recommended that you first recover all your data. Use a professional data recovery tool such as Disk Drill to safely recover and store all your files onto an accessible drive. Once all your data is securely located on another drive, you can now fix your GPT partition table without worrying about data loss. First, click the Windows key and type “computer management” into the search bar and press Enter. Click on Disk Management. Select the GPT partition that you’d like to fix and right-click on it. Then, click on Format from the drop-down menu. This should successfully repair your GPT table.