Starting multi excel instance runs into problems whenever there is any add-in is enabled.

Question

I have a domain user needs to use multi excel instance every day. Recently when he tries to start a new excel instance, as long as there is any excel addin currently enabled, then the startup of 2nd instance will take long loading, eventually prompts error saying, "Excel is running into problems with 'c:\program files\microsoft office\root\office16\library\analysis\analys32.xll'. Disable this add-in and check for available updates. Do you want to disable it now?"

I looked around checking what the issue was and had no luck. Below are some items i tested.

1. The error is not limited to the particular add-in. All third-party plus excel native add-ins (Analys and Solver) will get this error prompt as long as there is any add-in enabled at the moment of starting the new excel instance.
2. The error will not occur when starting new excel instance in safe mode or simply just disabling all add-ins beforehand.
3. Other Windows user login the same PC and test the multi excel instances, no such error.
4. System restart, M365 Apps repair (quick and online), M365 Apps updates, Windows updates, M365 Apps reinstallation (From control panel and using Revo uninstaller).
5. Deleted excel registry "HKEY_USERS\Software\Microsoft\Office\16.0\Excel", no luck.
6. Same Windows user even login to a different PC (first time logging into this different PC), the same excel error still persists.
7. No roaming profile setup in the environment. Only some folder redirections for Desktop, Document, Downloads, Video, Pictures. User's \AppData\Roaming is still local only.
8. From Application log, event viewer, it captured excel running error every time the user trying to start new excel instance while there is any add-in enabled. On both PC.

9. At first, I raised a ticket from M365 Admin Panel, later the support based on the no.3 & 6 and told me they cannot handle any further. They told the issue should be lying under Windows support team, but they are just M365 online support team.

The M365 support told me to erase the local windows profile on that PC and relogin again to see if the issue is gone. But since i had the user to login on a different computer that he never logged into. I assume this is already equivalent to erasing the local profile plus login again. Yet the issue still persists.

Any idea of what happens and how to fix this? Thanks.

Answer 1

Hello, thank you for reaching out to the Microsoft Community. I'm here to help with your questions or issues.

Does the problematic user have custom group policies, logon scripts, or domain login-specific environment variables (e.g., %AppData%, %Path%, %TMP%) that differ from a clean domain user?

You already proved this isn’t an Excel install or machine issue (repros clean on new PC). It’s a user state problem, likely COM-related or policy-induced.

Don't wipe the profile yet. Extract the Office logs with SaRA (Microsoft Support and Recovery Assistant) under that user context, then cross-check OfficeAddinLoad traces from %LOCALAPPDATA%\Microsoft\Office\16.0\Telemetry\ to isolate what’s triggering the long hang before the error.

Answer 2

Hello, thank you for reaching out to the Microsoft Community. I'm here to help with your questions or issues.

Does the problematic user have custom group policies, logon scripts, or domain login-specific environment variables (e.g., %AppData%, %Path%, %TMP%) that differ from a clean domain user?

You already proved this isn’t an Excel install or machine issue (repros clean on new PC). It’s a user state problem, likely COM-related or policy-induced.

Don't wipe the profile yet. Extract the Office logs with SaRA (Microsoft Support and Recovery Assistant) under that user context, then cross-check OfficeAddinLoad traces from %LOCALAPPDATA%\Microsoft\Office\16.0\Telemetry\ to isolate what’s triggering the long hang before the error.

Hi Emmanuel,

Thanks for the reply.

I cross-checked the GPO applied to the user and others. Dont see any difference in there. No special handle to those environment variables.

I dont see Telemetry folder in the path. The SaRA retired and replaced by Get Help, so none of those work. I enabled the diagnostic data viewer on Windows and Excel. I feed it to Grok for quick analyzation, dont see any data is related to this excel multi instance issue.

Any more good suggestions? Thanks.

Answer 3

Thanks for the update. There are a few other things you can try:

Run this PowerShell under that exact user’s login:

$excelAddinsPath = "HKCU:\Software\Microsoft\Office\16.0\Excel\Options"
(Get-ItemProperty -Path $excelAddinsPath).PSObject.Properties |
Where-Object { $_.Name -like "OPEN*" } |
ForEach-Object { Remove-ItemProperty -Path $excelAddinsPath -Name $_.Name }

This removes stale OPEN, OPEN1, OPEN2, etc., which load XLLs even when the Add-In Manager is clean. One corrupt entry here will break multi-instance Excel every time.

Then, scrub HKCU\Software\Microsoft\Office\16.0\Common\General and AddIns subkeys. Delete all AddIns and AddIns2 keys. Then re-enable native add-ins from scratch (e.g., Analysis ToolPak) and test again.

Check both:

► %APPDATA%\Microsoft\Excel\XLSTART

► %LOCALAPPDATA%\Microsoft\Excel\XLSTART

Delete everything inside. Rogue PERSONAL.XLSB or dropped XLLs auto-load silently here and break new Excel processes.

With this, you’ll be clearing hidden auto-load entries from Excel → wiping any broken add-in registrations from the registry → deleting silent startup files.

Let me know if it worked for you.

Answer 4

Hi, thanks for the suggestions.

1. Removed all OPEN like keys under HKCU\Software\Microsoft\Office\16.0\Excel\Options
2. Deleted the Addins keys under HKCU\Software\Microsoft\Office\16.0\Common\General
3. Checked %APPDATA%\Microsoft\Excel\XLSTART, it is empty inside by default, on both computers. Nothing to delete.
4. No such path: %LOCALAPPDATA%\Microsoft\Excel\XLSTART , on both computers

Result: Nothing's change. Multi instance start up is still having the same error.

I also asked my user to login the m365 account to Excel on his personal computer that is not under our domain. Multi instance is work fine there. Next thing I am going to test out is to put a test domain computer in the OU that has no GPO (probably just no Computer Configuration) applies to it at all.

Do you have any idea that can possibly to eliminate the factors?

Answer 5

I think this is one of those cases where 1 bad DWORD under a buried GPO registry key breaks everything.

Run gpresult /h report.html on a working domain user and the affected user on the same machine. Compare line by line. GPOs can apply hidden Excel add-in policies via:

► User Config > Admin Templates > Microsoft Excel > Excel Options > Add-Ins

► COM object trust management

► LoadBehavior enforcement

Even “Block all unmanaged add-ins” silently fails multi-instance if the load context changes.

You can also compare this registry with a working domain user: HKEY_CURRENT_USER\Software\Classes\CLSID