Iris Classon
Iris Classon - In Love with Code

Visual Studio error: CleanWPPAllFilesInSingleFolder evaluates to '' instead of a boolean

Had this fine problem today, here is how I was able to solve it. Of course this seems to be more of a ‘fix’ than a permanent solution, but maybe I can help a few more devs :)

I’m currently using VS2013 Preview (updating to RTM next week), but this error exists in VS2012 as well.

How the error looks like:

Exception in executing publishing: Specified condition “$(CleanWPPAllFilesInSingleFolder)” evaluates to "” instead of a boolean.C:\Program Files (x86)\MSBuild\Microsoft\VisualStudio\v12.0\Web\Microsoft.Web.Publishing.targets

publishing error from visual studio CleanWPPAllFilesInSingleFolder evaluates to instead of a boolean

Something not right about here…

Snipped from the document:

[sourcecode language="XML”]

<_CleanWPPIfNeedTo Condition=”‘$(_CleanWPPIfNeedTo)’ == '’ And ‘$(CleanWPPAllFilesInSingleFolder)’!=’'“>$(CleanWPPAllFilesInSingleFolder)</_CleanWPPIfNeedTo>

When the error presents itself => during preview and/or publishing

CleanWPPAllFilesInSingleFolder evaluates to when publishing
The fix
  1. Close all documents for the solution

  2. Clean and build

  3. Close Visual Studio

  4. Restart as admin

  5. Click publish but DO NOT USE THE PREVIEW

  6. Proceed with publishing


Leave a comment (via email)
10/13/2013 1:15:38 PM
Yes, I have had this issue many a time (while colleagues didn't), after cleaning and re-building solution it seemed to work for a bit and as you mention restarting as admin got round it for me for a while, but then it started again. I went through a number of different solutions to see if I could pin point this issue, but I only managed to stop it occurring when I stopped previewing before publishing, so I think there may be an issue with the preview feature in VS12 & VS13. 
10/27/2013 12:44:57 AM
Thanks, this post saved me a headache. 
1/14/2014 7:19:08 AM
If you know for sure that you won't publish as a single assembly
will work just fine. 
Lee Englestone
3/24/2015 1:52:21 AM
Wow, this still seems to be an issue to this day..
I'm using Visual Studio 2013, Community Edition, made the mistake of pressing Preview (that failed) and then subsequently got that error. Restarting VS worked though. Thanks. 

Last modified on 2013-10-02