What will happens when you find your partition is missing from your computer. It may not be lost or deleted as the space is still utilized, but it will be hided. It is not safe to use unsecure third party software for unhiding partitions and you need not depend on these as you already have Command Prompt in Windows which is an inbuilt feature.
Step 1: Click on Windows key and type cmd or command prompt.
Step 2: Right click on the Command Prompt tool and run it as administrator or use the short cut ctrl + shift + Enter to run it as administrator.
Step 3: Please type diskpart in the command screen and press enter to open diskpart menu.
Step 4: Then type the command list volume and press enter key to view partitions. You can see the list of volumes and the information about the volumes.
Step 5: Here the volume 3 does not have letter and it is hidden, (You can check the size of the partition) so we need to assign a letter for this particular partition. Type select volume 3 and press enter to choose the volume 3.
Step 6: To assign a letter for volume 3, please type assign letter g and again click enter.
Once the above mentioned steps are completed, you will get a command - "diskpart successfully assigned the drive letter or mount point". Now open my computer and check the partition is displayed or not. You can use third party software to hide and unhide partitions if the above mentioned steps are difficult for you, but if the tool is not reliable it will affect your partitions badly. Sometimes, it may even wipe out your partitions forever. It is always advised not try with such software. In case if you come across such situations, you need to use any strong recovery tool to recover the partitions. So it is better to use manual method which is easy and will save your money.