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httpRuntime targetFramework 4.5 issues


We're running into some issues with asynchronous tasks crashing, and some of them led us to believe our EpiServer site is not running under 4.5.  In our web config, the compilation targetframework was set to 4.5, but there was no attribute on the httpRuntime element to tell it to use the 4.5 framework, so I believe (unless someone knows otherwise) that this means we're compiled to 4.5 but running in quirks mode.

Based on that we, went ahead and added targetFramework="4.5" to the httpRuntime element in the web config.  This seems like it does get our asynchronous code running under 4.5 correctly, and at a glance, the site seems to work.  However, when we log into the content editing area, the content tree does not load.  That pane just seems to never load.

Is it a known issue that EpiServer admin area does not work under runtime 4.5, and if so, what is the latest runtime that it supports?  Anyone successfully get it working?


Sep 11, 2014 22:59

Sorry, should have noted, we are running EpiServer 7.8!

Sep 11, 2014 23:00

Just want to note that from 7.13 we switched to .NET 4.5 and it'll be a requirement to run EPiServer CMS. 


Sep 12, 2014 2:00

Hi Quan Mai

Is there any announcement or link regarding to switch to .NET 4.5 from episerver? 

Sep 16, 2014 5:48

Actually, the switch will not be made until the 7.14 release that is currently planned to go out on Friday. We'll have more information about the switch around the time for the release.

Sep 16, 2014 6:20

Thank Linus for the correction!


Sep 16, 2014 12:15

Will that be .NET 4.5 or .NET 4.5.2?


Sep 16, 2014 13:04

We will:

  • Build on 4.5.
  • Support any flavour of 4.5 (4.5, 4.5.1, 4.5.2).
  • Recommend that you run on 4.5.2.
Sep 16, 2014 13:30

Sorry to resurrect this thread - but I'm seeing the same thing on CMS 7.19.1.

After updating our external dependencies to use async/await I had to specify the targetFramework to get it running.
But afterwards I get the same thing as swc describes, the content tree is blank and I don't see any ajax-calls returning anything else than status 200.
Removing the targetFramework flag gets me the content tree - but no sane context during asynchrony.

Has anyone successfully got this working or got pointers?

Mar 10, 2015 8:40


I wouldn't expect it to be an issue in 7.19 - it should be run correctly in 4.5.2 already based on the info in this thread.  If you upgraded or something, perhaps check your web config and ensure that you have aspnet:UseTaskFriendlySynchronizationContext set to true in your app settings as well?

Mar 10, 2015 15:24

Thanks for the response!
Yeah, I've set the appsettings flag as well, but no luck with that.

I now noticed that I can actually view all content, but everything switched places to the right side panel..
See screenshots below.


targetFramework omitted:

Mar 10, 2015 16:26

We have the same problem (empty page tree panel when targetFramework="4.5") with latest EPiServer 8.8.0, reproduced in all browsers. Anybody knows how to fix it?

Jun 10, 2015 18:08

We're having the same issues with the latest CMS 9.3. Did you have any luck fixing it?

Nov 05, 2015 13:53

EPiServer version: 9.3
Target framework for EPiServer project: 4.5.2

No content tree (the pane was gray) in edit-mode when having this:

If I removed the targetFramework attribute the content tree was back in edit-mode.

This was only for me, the other developers did not have the same problem. Something for me only, so I tried "MySettings.aspx", http://SITEURL/EPiServer/CMS/edit/mysettings.aspx. I did two things:

Changed from "Use system language" to "Svenska"
Clicked "Reset Views"

When I went back my tree was back. I then changed back to "Use system language" and the tree was still there.

So I guess "Reset Views" did it. Try and see if it helps.

Regards Hans

Nov 10, 2015 12:33

Old post but have to comment here as I faced the same "empty" content tree issue when updating an oldish Episerver site. In browser developer console there are JS errors from WidgetFactory.

Resetting views sorted this out, no need to change language.


  • login to CMS
  • open the top curtain menu
  • click your username in the top right corner
  • click My Settings
  • switch to the Display Options tab
  • click the "Reset Views" button

That should fix the empty content tree.

Nov 17, 2017 9:32
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