C drive is full. How can I extend C drive without losing data on Windows 10 PC?

You can shrink other partitions and extend C drive when C partition is full but nothing to delete. The free Disk Management utility is able to do this on Windows 10 and Windows 11 PC.

1. In Disk Management, right-click on an adjacent partition (like D drive) and select Shrink Volume.
2. Choose the amount of space to shrink, then shrink the volume. This will create unallocated space.
3. Right-click on the C drive and choose Extend Volume to incorporate this unallocated space.

Warning: Tip: If the unallocated space is not adjacent to C drive, this method may not work.