This error happens very frequently when an Excel VSTO project is built and run within VS. The Excel file will open, but this error will occur.

The way I deal with it is to close the Excel file and restart it within VS again, or and again, or and again, or and again, .... The error usually will disappear after rerunning the application once, or twice, or thrice, ... Sometimes, I do have to close VS and restart the whole thing.

Could anyone offer a better remedy?

I am using the latest versions of VS and VSTO.

The details of the eroor are copied as following:

Could not load file or assembly 'AB5000Trend, Version=1.0.2309.22694, Culture=neutral' or one of its dependencies. The process cannot access the file because it is being used by another process. (Exception from HRESULT: 0x80070020)

************** Exception Text **************
System.IO.FileLoadException: Could not load file or assembly 'AB5000Trend, Version=1.0.2309.22694, Culture=neutral' or one of its dependencies. The process cannot access the file because it is being used by another process. (Exception from HRESULT: 0x80070020)
File name: 'AB5000Trend, Version=1.0.2309.22694, Culture=neutral'
at Microsoft.VisualStudio.Tools.Applications.Runtime.AppDomainManagerInternal.HandleOnlineOffline(Exception e, String basePath, String filePath)
at Microsoft.VisualStudio.Tools.Applications.Runtime.AppDomainManagerInternal.LoadStartupAssembly(EntryPoint entryPoint, Dependency dependency, Dictionary`2 assembliesHash)
at Microsoft.VisualStudio.Tools.Applications.Runtime.AppDomainManagerInternal.ConfigureAppDomain()
at Microsoft.VisualStudio.Tools.Applications.Runtime.AppDomainManagerInternal.LoadAssembliesAndConfigureAppDomain(IHostServiceProvider serviceProvider)
at Microsoft.VisualStudio.Tools.Applications.Runtime.AppDomainManagerInternal.ExecuteCustomization(IHostServiceProvider serviceProvider)

=== Pre-bind state information ===
LOG: User = ABIOMED.COM\hzhang
LOG: DisplayName = AB5000Trend, Version=1.0.2309.22694, Culture=neutral
(Partial)
LOG: Appbase = file:///C:/Documents and Settings/hzhang/My Documents/Software Projects/VSNET/Office/AB5000Trend/bin/Debug/
LOG: Initial PrivatePath = NULL
Calling assembly : Microsoft.VisualStudio.Tools.Applications.Runtime, Version=8.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a.
===
LOG: This bind starts in default load context.
LOG: No application configuration file found.
LOG: Using machine configuration file from C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\config\machine.config.
LOG: Policy not being applied to reference at this time (private, custom, partial, or location-based assembly bind).
LOG: Attempting download of new URL file:///C:/Documents and Settings/hzhang/My Documents/Software Projects/VSNET/Office/AB5000Trend/bin/Debug/AB5000Trend.DLL.
LOG: No application configuration file found.
LOG: Using machine configuration file from C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\config\machine.config.
LOG: Policy not being applied to reference at this time (private, custom, partial, or location-based assembly bind).
ERR: Failed to complete setup of assembly (hr = 0x80070020). Probing terminated.

************** Loaded Assemblies **************
mscorlib
Assembly Version: 2.0.0.0
Win32 Version: 2.0.50727.42 (RTM.050727-4200)
CodeBase: file:///C:/WINDOWS/Microsoft.NET/Framework/v2.0.50727/mscorlib.dll
----------------------------------------
Microsoft.VisualStudio.Tools.Applications.Runtime
Assembly Version: 8.0.0.0
Win32 Version: 8.0.50727.42
CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/Microsoft.VisualStudio.Tools.Applications.Runtime/8.0.0.0__b03f5f7f11d50a3a/Microsoft.VisualStudio.Tools.Applications.Runtime.dll
----------------------------------------
Microsoft.Office.Tools.Common
Assembly Version: 8.0.0.0
Win32 Version: 8.0.50727.42
CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/Microsoft.Office.Tools.Common/8.0.0.0__b03f5f7f11d50a3a/Microsoft.Office.Tools.Common.dll
----------------------------------------
System
Assembly Version: 2.0.0.0
Win32 Version: 2.0.50727.42 (RTM.050727-4200)
CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System/2.0.0.0__b77a5c561934e089/System.dll
----------------------------------------
System.Windows.Forms
Assembly Version: 2.0.0.0
Win32 Version: 2.0.50727.42 (RTM.050727-4200)
CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Windows.Forms/2.0.0.0__b77a5c561934e089/System.Windows.Forms.dll
----------------------------------------
System.Xml
Assembly Version: 2.0.0.0
Win32 Version: 2.0.50727.42 (RTM.050727-4200)
CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Xml/2.0.0.0__b77a5c561934e089/System.Xml.dll
----------------------------------------

Hi,

I am not sure exactly what is causing this error. But as the error message says some process is using the AB5000.dll file and has it locked.

Is it possible that VS is still compiling this dll when Excel is launched? Accordingly to folks I have talked to this is very unlikely. VS would only lauch Excel once the dll is compiled.

Is it possible that some "left-over" instance of Excel is using the dll? No. Excel loads the VSTO assembly by making a copy of it (search for .NET appdomain ShadowCopy behavior).

Are you running an executable in a post-build step that might be using the file?

I would suggest you download Process Explorer tool from SysInternals website:
http://www.sysinternals.com/Utilities/ProcessExplorer.html

This is a great tool if you don't have it. Click Handle menu and type the "AB5000.dll" in the textbox and you get a list of processes with handle to the file. You can run your VSTO customization from VS and when you get the error message start Process Explorer. Hopefully, you can find the process(es) that has the file handle open. Please let us know what you find.

Thanks

Hi, thanks for all the suggestions.

1. I build the applications first, then run them, so it is impossible the compiling is still going on.

2. I start the applications only from VS.

3. I downloaded Process Exlorer and am running it now. The Handle menu is grayed. I used Find Handle or Dll and typed AB5000.dll and could not find anything.

I am still using the method of repeating restaring the application. Usually after 7 or 8 times, the error message will be gone. I have also noticed that if I swtich the build mode (e.g. from debug to release, or vice versa), it may accelerate the disappearance of the error message.

Hi, thanks for all the information.

The way my applications work is this:

There is a button called "Compute" on each wroksheet. There is no code for Sheet??_Startup(). My code is run only the button is clicked. In other words, I get the error before any of my code is executed. Therefore I doubt that the error has anything to do with my code. Very annoying.

hz

I don't think the error has anything to do with your code either. Because it happens much before the startup event is fired.

I think some process is definitely using the assembly file and thus has it locked. So, the VSTO loader fails to load the assembly. Neither VS nor the loader should be doing this. So, it's hard for me to say which process it the culprit.

1. Just to check, please give some details on the version of VS, VSTO and runtime you have installed?

2. Have you specified a post build step (e.g. an executable) in your project file?

3. Does this error only occur for one specific Excel project or for all Excel VSTO projects?

4. Can you create a new blank Excel VSTO project and see if the error occurs there

5. Do you also see the error when debugging Word VSTO projects?

6. What kind of machine configuration do you have?

Thanks

Hi I am still struggling with this error.

1. I am using the latest version of VS, VSTO received from MSDN subscription (last December?).

2. I am not sure what you mean by post build step.

3. It occurs on multiple Excel projects.

4. I have just created a new VSTO project and run it a few times and this error did not occur. However, the error is not predictable. It does not occur if I start everything fresh (e.g. rebooted my computer). It occurs usually after the VSTO application is run from within VS a few times.

5. I have never had a Word VSTO project.

6. I have a Dell Dimension 370 with P4 3.0 GHz and 2 GB RAM.

Thanks,

hz

Hi Apurva,

I have seen your post in the forum. I am also facing the same problem. My problems are...

1. Even if I create a new ExcelWorkbook project using C#. Immediately after creationg without adding any new code if I run it....Excel application is opened but the following error is showing...

"The customization assembly could not be found or could not be loaded. Yo can still edit and save the document. Contact your asministrator or the author of this document for further assistance."

2. I am using Visual Studio 2005. Microsoft Office 2003. Visual Studio Tools for Office 2005.

I can't run it for a single time.

It will be of immence help, if you could give some idea to how to bypass this kind of problem.

Saibal

Note : One thing I think I should mention here. Recently I have Updated my machine from Windows 2000 professional to Windows XP without formating my machine.

Thanks for the tips! I am sorry for delayed response.

Let me report an observation that may be a good lead before I try to answer the questions. I noticed that the error happens when I have two instances of VS open (I like to have two open so I can work on two unrelated solutions). It seems the error disppears when I close the other instance of VS with non-office application solution. I have not had that error when I have only one VS open. The error happened again, though not immediately, after I started another instance of VS. Since I have not tried this many times to verify this, I cannot gurantee this is 100% repeatable, but I will continue my observation and post it here if I see anything contradictory.

Does this mean anything?

hz

I am not sure but it seems like the problem is related. I regularly have many instances of VS open but I have never seen this issue personally.

Does the non-Office project open in the other instance of VS reference the VSTO customization assembly or one of the dependencies of the VSTO assembly?

Do you have any addins for VS that may be causing the problem?

Thanks

Yes, almost every one of my projects in C# references a project called CSCommon that is essentially a collection of frequently used functions of all kinds such as computing average, standard deviation, Fisher-exact tests, etc. However that project has not been touched for a while.

All the projects use Serena ChangeMan for source control. I do not know if this is the type of addins you referred to.

hz

Hi,

Have you been able to resolve this issue.

Thanks.

Hello,

Unfortunately I have not.

I have found that multiple instances of VS are not the cause of the problem. It seems that many things related to VS can be done to make the error disappear temporarily - switching build mode from debug to release, or vice versa, starting or stopping the VSTO application multiple times, closing another instance of VS, or closing and reopening the current instance of VS. Doing these things to deal with the error has become a part of my daily life.

hz

hz,

In a previous post when you ran process explorer you searched for "AB5000.dll". The assembly actually being locked is "AB5000Trend.dll". It really does sound like some process has AB5000Trend.dll locked and we need to determine what process it is. Perhaps you made a typo and actually did look for "AB5000Trend.dll" but I'd like to make sure.

Thanks.

Hi, I am sorry for getting back late and thanks for your attention.

Yes, you are right that I had a typo.

I used Process Explorer and found two entries both of which are devenv.exe.

PE does not allow me to copy the entries in text, but I captured as image. Is there anyway I can attach that image file this post because I believe the contents are quite telling.

hz

Hi,

You can mail them to me at apsinha at microsoft. I don't know much about Serena but if it loads an in-proc component (i.e. addin) into VS then that component could have causes devenv to lock the file. devenv.exe would appear as the culprit in Process Explorer. You might want to disable that completely and try building projects. Thanks.

Hi hz,

Has this issue been resolved? Do you need more help on this?

Thanks.

No. I still have this problem, but I can live with this.

No software is bug free. I just regard this as a bearable bug of VS, VSTO or Excel.

BTW, quite often Excel still exists in the background after I close everything. I have to use Task Manager to kill the Excel process that prevents me from doing anything with the file it holds.

hz