Last week a new build for Windows Technical Preview (“Windows 10”) was available. You can easily find out by going to PC settings: Windows + C > Settings > Change PC Settings > Update and Recovery > Preview Builds

 

My current version (build 9841):

 

Upon clicking install now I got the following error:

In words: Failed to install the new preview build, please try again later. 0x80246007

After rebooting and trying again:

In words: Couldn’t install Windows Technical Preview. We couldn’t update the system reserved partition.

In words: Failed to install the new preview build, please try again later. 0xC1900200

I opened up diskmgmt.msc to find out what was wrong with my system reserved partition:

As you can see the first partition (system reserved) was quite full. I assigned a drive letter and starting looking around. The easiest way to do this is to use PsExec (http://technet.microsoft.com/en-us/sysinternals/bb897553.aspx) and start a command prompt as System (psexec –s cmd). If you use a regular command prompt you’ll get some access denieds here and there as your local administrator user might not have access to some system managed files/folders. Using dir /a you’ll be able to drill down the structure. Eventually I came up with H:\Recovery\WindowsRE\ which contained a file WinRE.wim of 309 MB.

This WinRE.wim contains a Windows Recovery Environment which you can boot when your system is having issues. It’s not vital that this is stored in the system reserved partition so I thought Id move it. Using “reagentc.exe /info” or “bcdedit /enum all” you can also see this configuration:

I then started messing around with takeown and eventually I just used Windows Explorer and moved the Recovery folder to my second internal HDD (D:\) which I use as a data volume. After moving the files I could see that the WinRE configuration was disabled. I googled around a bit to find out how I could update the information to reflect the new location. There seemed to be a reagentc command available, but although it stated success my configuration wasn’t updated to reflect the new path. So I used Visual BCD (http://www.boyans.net/) to just easily change the BCD parameters:

I updated both Windows Recovery Device options (edit SdiDevice and chose D: as my partition)

The same for the Windows Recovery Environment loaders (edit  ApplicationDevice and OSDevice)

Now my configuration showed as enabled again:

After making some free room I could now successfully install the latest build:

Eventually it seemed that the update process also moved (or recreated?) the WinRE environment on my C:\ drive. The Recovery folder I moved was empty (besides the logs folder). Using reagentc /info I could also see that the WinRE.wim was coming from the C:\ partition. So I guess this worked out fine for me.

On a final note: there’s a new option available to set your preference as to how fast you want to receive new builds:

 

This is also explained on an official blog of Microsoft:blogs.windows.com: We’re rolling out our first new build to the Windows Insider Program