By Ailsa / Last Updated July 17, 2020

About Healthy primary partition

What is the healthy primary partition means? The healthy primary partition is a partition which stores Windows system/boot files (io.sys, bootmgr, ntldr, etc.), system restore files or other data. It is the only partition that can be set as active. Typically, the Windows will deploy one or more healthy primary partition. On a MBR disk, there can only be 4 primary partitions or 3 primary partitions plus 1 extended partition at most. For GPT hard disk, there can be unlimited primary partitions.

A healthy primary partition could be an EFI System partition, recovery partition, or healthy system active primary partition (usually the C drive), etc. In a word, the healthy primary partition no drive letter could be a normal state to show the typical EFI System partition, or a recovery partition, etc. Besides, a healthy primary partition not accessible anymore (primary partition has no drive letter) in Windows Explorer could be a problem due to some reasons. We analyze the following two cases.

Two Cases

Case 1: I have a Windows 7 computer shows these partitions:

1. Healthy, Active, Recovery Partition. 1.46GB.

2. C: Healthy, Boot, Pagefile, Crash Dump, Primary Partition. 451.3GB.

3. Primary Partition 13GB.

All these partitions are on Disk 0. It is the 3rd partition with no drive letter that I have questions. Can I add the 3rd partition to the C drive? This computer is factory partitioned. I have no idea about the 3rd partition and how to figure it out? Any help would be appreciated.

Case 2: Hi, I have a question that my healthy primary partition doesn’t have a drive letter somehow on a GPT hard drive in Disk Management. Thus, the healthy primary partition is not accessible anymore in Windows Explorer. Now I want to assign a drive letter for the healthy primary partition to show it. But I find that the Change Drive Letter option is simply greyed out only the delete volume option is available. What should I do to show the healthy primary partition?

Change Drive Letter Greyed Out

Solutions for Case 1: Healthy primary partition no drive letter issue

In the case 1, you could delete the healthy primary partition to get more free space if you ensure these files that you do not need anymore. Or you can back up the healthy primary partition before deletion. Then you can add the free space into the C drive to solve healthy system active primary partition with no drive letter. To do so, you can use Disk Management and a free partition manager.

Disk Management

  • On the desktop, select This PC->Manage to open Computer Management.

  • Select Disk Management under Storage.

  • Right click the healthy primary partition and choose Delete Volume to get an unallocated space.

Delete Volume

  • Then you can merge the unallocated space to the C drive to extend system partition in Disk Management.

Extend Volume

You should know Disk Management can only extend a partition with adjacent unallocated space on the right side. You are not allowed to extend the partition if the unallocated space is not behind it. In this situation, you can try a third-party partition software

The free partition software-AOMEI Partition Assistant Standard

This freeware will allow you to manage your hard drive, SD card, USB flash drive, and other memory sticks. You can split, merge, format, delete, move partition, assign drive letter etc. It is easier to use than Disk Management due to its advanced features and friendly interface; you could merge the c drive and the healthy primary partition with no drive letter with simple clicks. You don’t have to delete the healthy primary partition at first. Here is how to merge the healthy primary partition and the system partition (C drive) in Windows 7/8/10.

1. Download this freeware, install and launch it. Right click the C drive or the healthy primary partition without drive letter and choose Merge Partitions.


2. Tick the C drive and the healthy primary partition both, and then hit OK.


3. Click Apply to extend C drive.


Solutions to Case 2: Healthy primary partition with no drive letter

In the case 2, the healthy primary partition with no drive letter not showing up in Explorer, and the Change Drive Letter and Paths option is greyed out in Disk Management. Why your computer refuses to assign drive letter to the healthy primary partition? Here are some reasons:

  • The volume is not formatted to FAT or NTFS. If you attaching the drive is from the Mac computer, which means that the volume is formatted with Apple File System (APFS) and is not compatible with Windows OS. You have to format it to FAT or NTFS.

  • The drive is write-protected. If the hard drive is read-only, the Windows will not allow you to assign drive letter. Thus, you have to remove write protection from disk first, then you could assign drive letter.

After formatting to FAT/NTFS or removing write protection, go into Disk Management and assign a drive letter to it. And Look through your files on that healthy primary partition. In addition, you could use AOMEI Partition Assistant Standard to assign drive letter to it, here is the steps:

1. Execute the AOMEI Partition Assistant Standard, and select the Advanced->Change Drive Letter after right click the healthy primary partition.

Assign Drive Letter

2. Choose a drive letter for the healthy primary partition and hit OK.

Select Drive Letter

3. Click Apply to fix healthy primary partition no drive letter problem.

Apply Assign Drive Letter

Furthermore, you could format or delete a healthy primary partition if needed with this freeware.


Now, you must have repaired healthy primary partition no drive letter problem because of the best free disk partitioning software-AOMEI Partition Assistant Standard. Moreover, the advanced functions like allocate free space, split, format/delete/extend/shrink partition, covert primary partition to logical, migrate OS to SSD and so on are available in Professional edition. The Server edition covers all the advanced features of the professional for server users, and supports Windows Server 2003, 2008 (R2), 2012 (R2), 2016, 2019 and SBS 2003, 2008, 2011.