Microsoft Access "Class Not Registered" Run-time Error '-2147221164 (80040154)'
Written by Luke Chung,
You've created a Microsoft Access database solution
and have successfully distributed it to many people.
Everyone is running it properly but one machine is
triggering this error. The error message makes no sense
and everything you try fails to resolve the problem.
What's going on?
The MS Access database actually runs so it's compiled
and functional. It doesn't seem corrupt since others can
run the same database, yet this error appears when very simple
ADO code such as CurrentProject.Connection is run to open a table or query recordset:
We've actually had reports of this problem for years
but were never able to reproduce the problem. We finally
did and have a solution.
"Class Not Registered" is Unclear
The "Class Not Registered" message is very confusing.
Which class is not registered? And what's the problem
with this machine when the database runs successfully on
The message implies it is caused by code that won't compile, but the code compiles
and is running fine before this crash occurs.
Common techniques such as
the database make no difference.
Is it a broken library reference? Checking the list of referenced libraries doesn't reveal any problems.
Is the database corrupt?
The symptom can exist if you create a new database and run this in the Immediate Window:
This simple test effectively rules out any issues
associated with your database. This basic Microsoft
Access VBA command won't even run on a blank database.
The CurrentProject object is part of Microsoft Access.
It's not something a developer adds. The problem exists within MS Access, not your database, so the fix is at the Access/Office level.
One of the causes for this
error appears to be related to uninstalling another version of Access after your version of Access was installed. This
may include uninstalling runtime versions of Access.
For instance, your machine may have Access 2007
installed on it. Access 2013 was later installed, and
then Access 2007 uninstalled. Access 2013 seems to be
running properly but it fails when this code is run. For
some reason, the uninstallation of the prior version of
Access makes the current one you're running unstable.
It may also be related to the installation of Windows updates and security patches. And of course, it could be caused by unknown file corruptions. Thankfully,
this error doesn't happen often.
Solution: Repair Microsoft Office Access
The solution we've found is very straightforward. Just fix
(repair) the installation of Microsoft Office/Access.
You may need Administrator permissions to do this.
Go under the Control Panel, Programs, Programs and Features, select
"Microsoft Office Professional Plus 2013" (or your
version of Access) and click on Change:
When the next screen appears, select Repair:
It takes a while, but after Office and Access are
repaired, the problem goes away.
Confirm it's fixed by running Microsoft Access,
opening a database, and testing CurrentProject.Connection
in the Immediate Window. It should now work.
If it doesn't work, you may need to uninstall and
reinstall Microsoft Office and Access.
Hope this helps!