Announcing Windows 10 Insider Preview Build 16226 for PC Insider

waltc said:

I successfully installed 16226 as an upgrade over 16215, after first uninstalling .net 3.5. Problem is that now in 16226 I cannot reinstall .net 3.5 at all. *

Same problem here ... tried everything but cannot get .net 3.5 to install.

EdTittel said:

I, too, cannot get .NET Framework 3.5 (and older elements) back on my Dell Venue Pro 11 7139. Same error code as the earlier poster with the same problem. Here's a screencap:
Attachment 140687
My biggest problem with this comes from a handful of utilities -- including Core Temp/8GadgetPack, RAPR, Secunia PSI, and no doubt others -- upon which I rely. Alas, they apparently rely on older .NET versions, and won't work without said support loaded and running. Ouch!--Ed--PS: I posted to Feedback Hub on this, including a trace of the powershell stuff shown running and failing. Hopefully, that will help them. We'll see how long this sticks around...

Had this problem before, and here is how I got it to work. Follow this, and it should be all good. I hope it helps.
Once you have the Windows installation files in a known place, you can use the DISM (Deployment Image Servicing and Management) utility to enable NET 3.5 for you. For that, you need to open a prompt command in Administrator mode by searching for “command prompt”, right click on the icon and choose “Run as administrator”. You can then run the following commandism /online /enable-feature /featurename:NetFx3 /All /Source:F:\sources\sxs /LimitAccessinstall-net35-dismNote that in my case, my Windows installation files were on F: but this could be different on your system. Replace F: with the appropriate drive.This procedure is documented officially at http://support.microsoft.com/kb/2734782, but I thought that it lacked context and explanations. If you are lucky, NET 3.5 should now be installed and you can run your app!Unfortunately, I was not so lucky and I found myself facing a new error message: “Error 0x800f081f. The source files could not be found. Use the “source” option to specify the location of the files that are required to restore the feature. For more information on specifying a source location, see MSN.com - Hotmail, Outlook, Skype, Bing, Latest News, Photos Videos (the page links to Configure a Windows Repair Source which is how to configure a Windows Repair Source). Ultimately, none of the information contained in these pages did help me get this thing off the ground.install-net35-dism-errorNote that if you want to open the dism.log file, you may find yourself looking at a bit of text and a pile of garbage that look like Asian characters. This is because the text reader is not using the proper character encoding. I was able to read the log properly by opening the file in Word and hand-picking the UTF-8 encoding. The log didn’t provide any useful into to fix this, but at least I was able to discard it after that.

loquacious said:

Same problem here ... tried everything but cannot get .net 3.5 to install.

Try this as it is how I managed to get it straight on my machine.
Once you have the Windows installation files in a known place, you can use the DISM (Deployment Image Servicing and Management) utility to enable NET 3.5 for you. For that, you need to open a prompt command in Administrator mode by searching for “command prompt”, right click on the icon and choose “Run as administrator”. You can then run the following commandism /online /enable-feature /featurename:NetFx3 /All /Source:F:\sources\sxs /LimitAccessinstall-net35-dismNote that in my case, my Windows installation files were on F: but this could be different on your system. Replace F: with the appropriate drive.This procedure is documented officially at http://support.microsoft.com/kb/2734782, but I thought that it lacked context and explanations. If you are lucky, NET 3.5 should now be installed and you can run your app!Unfortunately, I was not so lucky and I found myself facing a new error message: “Error 0x800f081f. The source files could not be found. Use the “source” option to specify the location of the files that are required to restore the feature. For more information on specifying a source location, see Configure a Windows Repair Source (the page links to Configure a Windows Repair Source which is how to configure a Windows Repair Source). Ultimately, none of the information contained in these pages did help me get this thing off the ground.install-net35-dism-errorNote that if you want to open the dism.log file, you may find yourself looking at a bit of text and a pile of garbage that look like Asian characters. This is because the text reader is not using the proper character encoding. I was able to read the log properly by opening the file in Word and hand-picking the UTF-8 encoding. The log didn’t provide any useful into to fix this, but at least I was able to discard it after that.

6 times a charm? Apparently not!
I give up!