The Windows operating system lets you extend any volume provided there is free or unallocated space on its right side. If there is no unallocated space, you will not be offered this option and it will appear grayed out.
Why is the Extend volume option grayed out?
These could be the possible reasons for Extend volume option grayed out. This could occur if there is no unallocated space on your hard drive. Also, if there is no contiguous unallocated space or free space behind the partition that you want to extend. Lastly, Windows can’t extend is a FAT or other format partition.
How do I fix Extend volume option grayed out?
If you need to extend the volume, you will need to delete the partition on the right side, i.e., behind the partition you want to extend and create unallocated space. If it is your Data Drive that you want to extend, then there is a workaround. Say you have a System Drive – C and a data drive – D. You want to extend D drive, but the option is grayed out. What you can do is Shrink the System Drive to create unallocated space, which will be on the left side. Create a new volume with this unallocated space. Then move your data from the D drive to this new volume. Having done this, delete D Drive and then you will be able to extend the new drive since there will be unallocated space now on its right side. If it is your C or System Drive that you want to extend, copy all your data from your D or data Drive to an external drive or USB. Then delete the D volume. Now you will be able to extend C Volume. Utilize the space you want to, and then with the remaining unallocated space create a new volume and name it D. Now transfer your data back to the D drive from the external drive.
A few points to note about extending volumes, as mentioned by TechNet:
Why is Extend volume disabled in Windows 11/10?
When you see the Extend Volume option grayed out on your computer, it signifies that there is no unallocated space on your hard disk. As there is no unallocated space after the C partition drive, so “Extend Volume” option is disabled. In this situation what you can do is, free up some space first, then you can extend your partitions. There are some free Partition Manager software that can help make the job of deleting, merging, and extending volumes easier. You might want to take a look at them. TIP: See this post if the Delete Volume option is greyed out.
