Excel Visual Studio Design Time Adapter Add-in Error

Question

I am trying to open excel workbook 2003 using VSTO. but i am getting error again again like

" Project cannot be created because the application add-in is not working correctly and might have been disabled. To check for disabled items in the Microsoft Office application, open the Help menu, click About Microsoft Office Word or About Microsoft Office Excel, and then click Disabled Items. If either "Word Visual Studio Design Time Adapter Add-in" or "Excel Visual Studio Design Time Adapter Add-in" appears, select it and click Enable. If not, reinstall or repair your installation of Visual Studio Tools for Office."

Can somebody help ??

Frenulum

Have you tried following the instructions? What happens? Which version of Visual Studio are you using? – Impeach

hey i was using visual studio 2008 and excel 2003. i tried many thing s..installing and uninstalling MS office ,VSTO . but what finally helped me is the UNISTALIING visual studio 2008. It took some time but finally its working and that's important for me. – Frenulum

Answer 1

In some cases you just have to close EXCEL.exe from running with TaskManager. I had the same issue and now it works.

Testimonial

Damn Damn Damn.. it was as simple as this! – Kermis

Answer 2

Maybe this is the same problem I was having with Design Time Adapter errors using VSTO

Just before repairing the install, as is advised, I had a quick check of the Task Manager, and noticed that an Excel.exe process was still running. Ended this process, and hey presto, it fixed the problem.

It appears that sometimes when debugging/running your project, if it fails or stops before the Excel app gets closed by your code, the design time adaptor hangs. This happened to me because an Automation Excetuable had left an instance of Excel up and running in visible = false mode.

Notebook

I spent an hour and all it took was to open the task manager.. Ugh! – Kermis

Answer 3

I am from the future, year of 2020, but I had the same issue despite using Office 365, Windows 10, and Visual Studio 2019. Visual Studio Design-Time Adapter Add-in (in my case it was Excel, but that's hardly relevant) kept disabling itself after each restart of Excel.

Reinstalling VSTO components didn't help, and I did not want to mess with the whole Office/VS re-installation.

The problem was solved by changing the value of HKEY_CURRENT_USER\Software\Microsoft\Office\Excel\Addins\VS15ExcelAdaptor key in the registry from 0 to 3.

Penetralia