How to merge two partitions in windows 11/10 without losing data?

There are a few things you should pay attention to when using the cmd (diskpart) to merge two partitions in Windows 11 or Windows 10.

Do NOT merge partitions without backing up data

DiskPart deletes the partition you want to remove, erasing all data on it.

Always back up important files before deleting or modifying partitions.

Do NOT try to extend a partition into non-adjacent unallocated space

DiskPart’s extend command only works if the unallocated space is immediately after (to the right of) the partition you want to extend.

If unallocated space is not contiguous or on the left side, DiskPart can’t extend.

Do NOT delete the wrong partition

Double-check partition numbers and sizes before deleting.

Accidentally deleting the wrong partition can cause data loss and system instability.

Do NOT merge partitions with different file systems

You cannot merge partitions formatted with different file systems (e.g., NTFS and FAT32).

Both partitions should ideally be the same type (usually NTFS).

Do NOT merge system or boot partitions carelessly

Merging or deleting system partitions (like the C: drive or EFI system partition) can make your system unbootable.

Avoid modifying system-critical partitions unless you fully understand the consequences.

In short, please don't forget to backup the data before merging two partitions without losing data in Windows 11/10.