{"id":1026,"date":"2016-07-18T01:07:00","date_gmt":"2016-07-17T23:07:00","guid":{"rendered":"http:\/\/borncity.com\/win\/?p=1026"},"modified":"2022-09-23T00:31:00","modified_gmt":"2022-09-22T22:31:00","slug":"windows-10-upgrade-disk-controller-current-active-partition-is-compressed","status":"publish","type":"post","link":"https:\/\/borncity.com\/win\/2016\/07\/18\/windows-10-upgrade-disk-controller-current-active-partition-is-compressed\/","title":{"rendered":"Windows 10-Upgrade: "Disk Controller: Current Active partition is compressed""},"content":{"rendered":"

Some users of Windows 7 SP1 (and probably Windows 8.1) are facing a curious error during upgrade attempt to Windows 10. The upgrade wizard refuses an upgrade with a note \"Disk Controller: Current Active partition is compressed\". Here a few hints how to proceed.<\/p>\n

<\/p>\n

\"\"Recently I stumbled upon this issue in a German Microsoft Answers forum entry<\/a>. But a short internet search shows, that several cases has been raised up since mid June 2016 (here<\/a>, here<\/a>, here<\/a>). The error will be reported from compatibility wizard during checking Windows 7 SP1 for compatibility before upgrading to Windows 10. The screenshot below has been made in a German Windows 7 (I haven't an English screenshot).<\/p>\n

\"Upgrade-Assistent<\/p>\n

A typical recommendation (see<\/a>) is to \"check, whether the Windows install partition is compressed or not\". While it looks \"nice\", it's the wrong approach. So I decided to track things a bit down.<\/p>\n

Which partition is active?<\/h3>\n

Before we try to check the logical drive's compression flag, it would be wise, to check which partition is active.<\/p>\n

1. Enter comp <\/em>in the Windows 7 start menu search bar and select Computer Management <\/em>with a right mouse click. <\/em><\/p>\n

2. Launch Computer Management <\/em>using context menu entry Run as administrator<\/em>.<\/p>\n

<\/p>\n

3. Navigate in the left pane to Storage\/<\/em>Disk Management <\/em>and wait, till the disks are shown (see also here<\/a> and here<\/a>).<\/p>\n

Side note: The problem should only occur on BIOS\/MBR disks, because GTP disks on UEFI systems doesn't have an active partition. UEFI systems uses an EFI partition to boot. The screen shot shown above has been taken on an UEFI\/GPT disk.<\/p><\/blockquote>\n

<\/p>\n

Here is another screenshot from a BIOS\/MBR disk. The screenshot shown above indicates, that the partition \"System Reserved\" is the active one. So it doesn't make sense to recommend \"checking the Windows drive for compression flag\".<\/p>\n

Grant a drive number to active partition<\/h3>\n

If partition Sytem Reserved<\/em> is set to \"Active\", assign a drive letter, using Disk Management.<\/p>\n

1. Right click the active partition in Disk Management and select Change Drive Letter and Paths.<\/em><\/p>\n

2. Assign a drive letter in the dialog box shown using the Add button.<\/p>\n

Note: Keep in mind, to remove the drive letter, after you have checked the compression flag as discussed below.<\/p>\n

Is the partition compressed?<\/h3>\n

After assigning a drive letter to the active partition, check the compression flag, using the steps below.<\/p>\n

1. Open explorer window, right click the logical drive containing the active partition.<\/p>\n

2. Use context menu entry Properties<\/em> and select the General <\/em>tab (as shown below in the sample screen shot \u2013 but note, the disk isn't necessary drive C:).<\/p>\n

(Source<\/a>)<\/p>\n

If the check box Compress this drive to save disk space <\/em>is checked, the root cause for the error is found. In this case, uncompressing the drive is recommended (see below).<\/p>\n

Some additional theories<\/h3>\n

If the active disk isn't compressed, but upgrade wizard reports the error mentioned above, the question is \"why\". Here are a few theories.<\/p>\n