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Issue with theme css references in EPiServer UI masterpage


We are having a strange issue in the EPiServer UI. After a re-build and first accessing edit/admin mode then all pages render correctly. After seemingly random periods of time the .net theme system appears to not recognise the "Default" theme and doesn't insert any of the css references into the header of EPiServerUI.master creating some strange looking Edit/Admin mode pages. The missing css references are App_Themes/Default/Styles/ToolButton.css and App_Themes/Default/Styles/system.css

The application is running CMS 6 R2, Composer, Commerce, .net 4,0, ADFS and ImageVault. 

Only a rebuild fixes the issue which suggests its something in the temporary files thats getting modified during the application execution and causing the problem (just guessing here). We have tried explicitly setting the <page theme="Default" and the <siteSettings ... uiTheme="Default" attributes with no sucess.  

Has anyone ever come accross anything like this before?

Oct 20, 2011 17:59

Can we see a screenshot? 

I would double check that my virtual paths to App_Themes and Shell is correct. Maybe even changing them to something wrong and then changing them back again, just to force the change. 

Edited, Oct 24, 2011 13:15

Hi Toni, thanks for the reply (for some reason I didn't get an email when you replied). 

I can't provide a screen shot right now but I did compare the HTML generated when things were going wrong. The only difference is the missing css theme files. As mentioned previously its the .net theme system that is failing to insert the css files from the App_Themes folder. 

The App_Themes virtual mapping is definitely pointing to the right place as its all OK on start up, its after a while things start going wrong.

I will see if I can recreate the error as we have since worked around the problem by overriding the EPIServer masterpage with a custom version that inserts the css files explicity, rather than relying on the .net theming system.


Nov 02, 2011 21:00


Try this:

1.Copy /MyEPiServerSite/App_Themes to C:\Program Files (x86)\EPiServer\CMS\6.1.379.0\Application

(App_Themes is already present here, paste and overwrite the file structure)

2. Stop or restart IIS

3. Go back to /MyEPiServerSite/ and rename (or delete) App_Themes

4. Reload the site. Done, UI should be back to normal.


Hope this solves it!



Feb 29, 2012 17:07

Please note:  Any changes made in C:\Program Files (x86)\EPiServer\CMS\6.1.379.0\Application will affect ALL sites on the server so be cautious when using that approach

Aug 20, 2012 4:26
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