error CS0012: The type ‘IEnumerable’ is defined in an assembly that is not referenced.

I was setting up a new build server for a .NET project as I have done several times before. It was a TeamCity build server but that is not important for this problem. When trying to build my solution I got this error:

error CS0012: The type 'IEnumerable<>' is defined in an assembly that is not referenced. You must add a reference to assembly 'System.Runtime, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'.

Locally the solution compiled just fine. After some research I found some hints that installing the Targeting Pack for my .NET Framework version solves the problem.

I downloaded and installed the target pack for .NET 4.6 from here. Immediately the problem was solved and the solution compiled without any problems.

It compiled locally because the missing DLL that is installed by the Targeting Pack is also installed by Visual Studio. This is just another reason to think about the “no Visual Studio on the build server” rule.

Powershell OpenFileDialog is not showing up

Recently I was writing scripts that should run on a Windows 7 machine. One task was to select a file and read it. So I used the usual snippet:

$OpenFileDialog = New-Object System.Windows.Forms.OpenFileDialog
[void]$OpenFileDialog.ShowDialog()

I ran the script from PowerShell ISE during development and everything worked fine but when the users executed the script, the file dialog did not open up. Then I came across this page here and it said ShowHelp solves the problem. I changed the script to:

$OpenFileDialog = New-Object System.Windows.Forms.OpenFileDialog
$OpenFileDialog.ShowHelp = $true
[void]$OpenFileDialog.ShowDialog()

I am not sure why, but this solved the problem and did not cause any other side effect. I am wondering what ShowHelp actual does because it seems to have no visible effect.

SharePoint stops writing log files

Recently I had a SharePoint installation that stopped writing log files without any clear reason. Restarting the timer service or the whole server did not solve the problem. The only thing I noticed was this entry in the event viewer:

Tracing Service failed to create the trace log file at location specified in SOFTWARE\Microsoft\Shared Tools\Web Server Extensions\15.0\WSS\LogDir. Error 0x0: The operation completed successfully. . Traces will be written to the following directory: C:\Users\SVCSPD~3\AppData\Local\Temp\.

Something seemed to be wrong with the log directory but the folder and its permissions looked totally normal. So I opened the Monitoring Settings (Central Admin -> Monitoring -> Configure diagnostic logging), change the path of the trace log to c:\temp and back to its normal location. As soon as I saved the second change, log files started appearing again.

shareoint_monitoring_setting