[.net] Visual Studio popup: "the operation could not be completed"

When I try to open a project, local or on a Team Foundation Server (TFS), I get a modal window telling me that:

The operation could not be completed: Unspecified error

Or the same message, but with "Class not defined.." instead of "Unspecified error".

These errors started happening earlier today when I tried to check in some of my work to the team foundation server. I have tried using Visual Studio 2008 on the same computer, but I still get the same error. I've also googled for it but none of the solutions seems to help me.

I have installed the latest updates from Windows Update as well.

Any ideas?

Restart the visual studio as Admin will work on in many cases.

For me, this issue was being caused by conflicting <site> configurations in the following file.

C:\Users\smunro\Documents\IISExpress\config\applicationhost.config

I edited this file to remove all of the site elements within the following element. You might want to be a little more selective and try to identify the site that is causing the conflict and remove just that.

<configuration><system.applicationHost><sites>

Note that I left the <siteDefaults>, <applicationDefaults> and <virtualDirectoryDefaults> elements there.

When I reloaded the project, a new <site> element was created automatically.

Run eventvwr from the command line to see if it has recorded any Application errors.

This might give you an actual error message that is more useful.

I removed an old project from the solution, after that the error occurred. I had to open the .sln file in notepad and delete the .dll reference tot he old project that I removed. After that it worked.

I deleted all .suo and .user files and restarted VS 2008. But it didn't worked for me. The following steps worked for me.

Open project file (.csproj) in notepad.
Removed all configurations from <Configurations></COnfigurations> tag.
Then add one by one configuration and reload project in VS.
Build the project or view project properties.

The error can also happen if you're in the folder in Windows Explorer or another app as you try to delete it from VS or have the file opened in another app. Windows has the habit of locking folders and files, especially on networked machines. It is possible to break the lock by using Process Explorer occasionally, but the simplest thing to do is to get out of the folder or close the file in question.

In our, the problem appeared after making changes in Debug -> myProject Properties -> Web, specifically changing the project URL and then closing VS. Upon reopening, VS had trouble parsing the new URL and so threw the error. Unfortunately, further configuration through the VS UI was not possible since the project won't load.

Since the file configuration changes are persisted in the myProject.csproj.user file, which lives in the project's root folder, the problem was easy to correct by simply removing the myProject.csproj.user file. At that point the project would load and the user file was then regenerated when the project was next run in debug mode.

Note, the project URL in the regenerated file had to be changed from the default http://localhost:58995 to the original https://localhost:44302 before the entire application could be accessed since we have the app locked down under SSL. Your ports may be different. This was done through VS under Debug -> myProject Properties -> Web after running the project.

I ran into this same problem but deleting the .suo file did not help. The only way I could get the project to load was by deleting the "Your_Project_FileName.csproj.user" file.

--

I ran into this problem again a few months later but this time deleting the "Your_Project_FileName.csproj.user" file didn't help like it did last time. I finally managed to track it down to an IIS Express issue. I removed the site from my applicationhost.config and let Visual Studio recreate it, this allowed the project to finally be loaded.

In my case, 'Silverlight 5 SDK' was missing and so my silverlight projects are not getting loaded. While trying to reload project it shows “the operation could not be completed” message. Once i installed, problem is solved.

If you are using Visual studio 2015 and working on ASP.NET, create a new website, copy the previous files into the new site and build your site. Your old project is still referencing some old startup parameters.

While working on VB.Net projects in Visual Studio 2005, I have faced this issue many times. Usually, disabling the 'Enable the Visual Studio hosting process' option in the application's debug properties solves the issue for me. Usually, when the hosting process is enabled, calls to certain APIs can be affected.

To un-check this option, you need to follow the steps below:

• Right click on your project in the Solution Explorer
• Select properties
• Under Debug tab, you would find a check box option for Enable the Visual Studio hosting process. Un-check this option.
• Save your changes

For me it was because I'd added an entry to bind the site in IISExpress to a specific IP address, and my IP address had changed. I got a clue from the event log.

Hope this helps someone!

For Visual C++ projects, this can be caused by an improperly formatted vcsproj.filters file.

In my case, someone had performed a manual branch merge and didn't merge the filters file correctly. Visual Studio still loaded and built the file without any warnings, but would give the 'unspecified error' warning whenever trying to add or remove files from the project.

Scan your vcsproj.filters file for any duplicate entries or lines that look like this and remove them. Close and reopen the project.

<ClInclude Include="..\..\path\to\sourcefile.h" />

Visual Studio Enterprise 2017

I had similar problem in iOS project in vs 2019,it's running on VM in Mac, I close and restart the visual studio, the issue was gone

Restarting Visual Studio solved my problem :)

Sometimes it is just a matter of closing Visual Studio 2015 and then open again.

Update: Visual Studio 2017 apparently as well.

I have had this happen on a few machines.

This does happen.

"Have you tried to delete the "Your_Solution_FileName.suo" file?"

Also computer crashing like e.g. power outage etc...

Applies to Update 2 and Update 3 as well as fresh base without any updates...

For this problem, I resolved it by deleting the .user file which contains the Visual Studio Project User Options. This File can be found in the same place where your .sln file is located. Also, after deleting this file from the project make sure to reload your solution in order for it to take effect.

I had same error. I couldn't open any class and component of my solution. I deleted the ComponentModelCache and tested any other solutions.. but no result. Finally it helped me: Just CLOSE YOUR VISUAL STUDIO AND AGAIN OPEN IT!

Worked for me after I closed Visual Studio (2015 Community Edition), opened it and opened project again.Had Happened to me because I was using this project as a dependency in another project and it was opened in another instance but the changes were not imitated.

No more .SUO files, but deleting .user files works. FYI: I am debugging Silverlight project

VS 2015 -> Deleting all the files in the ComponentModelCache worked for me:

C:\Users\**username**\AppData\Local\Microsoft\VisualStudio\14.0\ComponentModelCache

None of the solution above worked for me. But following did :

1. Open the current folder in Windows Explorer
2. Move the folder manually to the desired location
3. Open .csproj file. VS will then automatically create the .sln file.

I was upgrading to .NET4.6 from a 3rd party app (unity3d). I would get this message when I tried to reload the solution when it wouldn't load on startup. My solution was right clicking the solution and selecting "install missing features" which prompted me to download what I needed. The download on the popup didn't work so I just installed the .NET targeting pack for what I was on (4.6) and this fixed it.

I think StyleCop is the reason of the this issue. So,

1. Close VS.
2. I removed all StyleCop.Settings and StyleCop.Cache files in all solution projects.
3. I removed also all projects *.csproj.user file.
4. Restart VS.

Go to Run and type "inetmgr", i.e IIS is opened and in the right corner Action window, select option change ".NET Framework version". Change it.

After that, reinstall your Visual studio 2010. It works on my computer, and that's why sharing.

Solution: I was getting this dialogue when trying to build/rebuild/clean my .sln. To fix it I needed to stop the IIS site bound to the application and restart visual studio. (Then start your site again).

How I discovered the cause: Seems this is a pretty generic message for a wide range of issues, I ended up tracking down my particular issue to a few locked files by IIS with the event logs.

The solutions for deleting all sites are kind of a "Nuke it from orbit" approach which should be used as a last resort.

I had to remove a webproject. There was an old referencing DLL file inside, and I had to clean that webproject, and then it worked.

Make sure your Output Window is visible before hitting the F5 button. If you have your Output Window maximized, occasionally Visual Studio does not re-open the Output Window when you restart it.

Simple fix: 1. Restart Visual Studio 2. BEFORE building a project, use View->Output Window

Now when you build, it should work.

(I'm pretty sure deleting .suo and .user files only works because it resets Visual Studio to its default layout, which ensures the Output Window is visible.)

"The operation could not be completed" error can also be caused by a C++ project referencing another project that no longer exists in the solution.

Normally, when you remove a project from a solution, Visual Studio removes any references to it from other projects in the solution.

In my case, however, I was sharing projects between solutions hence a bad project reference managed to sneak in, and deleting the bad references fixed the error.

Using Visual Studio 2012.

I had a similar problem on opening Razor Views

• I logged on to my Azure account which was asking to re-enter my credntials.
• Restart VS 2015 Update 1