Earlier today, I decided to finally start using a Transcend solid state drive (SSD) that I had bought a few years ago. Since I was happy with the performance of my desktop computer, never installed the SSD until today (it was originally bought for my aging ThinkPad). After installing the SSD drive, turned on the PC. Naturally, the newly installed drive was not appearing in the File Explorer. So, opened the Disk Management. In the Disk Management window, the newly installed SSD was appearing, but when I right-clicked on the unallocated space of SSD to partition it, all options were grayed out. After looking at the screen for few seconds, I noticed this “Unknown, not initialized” for the SSD drive. If you have also installed a new drive and got “Unknown, not initialized” message in the Disk Management, here is how to fix the error by initializing the disk. Before you proceed to initialize the disk, remember that initializing disk will result in data loss. In other words, initializing the disk will erase the data on it, if any. So, if you have data on it, it would be better to contact a data recovery expert or use third-party tools to backup the data from the drive first before initializing. Usually, initialization required only for new drives. Initializing a disk in Windows 10 Step 1: Open the Disk Management. Right-click on the Unknown, not initialized message and then click Initialize Disk option. Step 2: When you get the Initialize Disk dialog, make sure that your disk number is selected, select the partition style as MBR (Master Boot Record) or GPT (GUID Partition Table) and then click OK button. Congratulations! You just initialized the disk. ` If you are confused between GPT and MBR, we suggest you select the MBR. If you want to convert MBR to GPT later, you can do so.