Microsoft Excel 2013 add-in not working after update

Question

I have originally posted this question at answers.microsoft.com and have been re-directed to post here. (http://answers.microsoft.com/en-us/office/forum/office_2013_release-excel/microsoft-excel-2013-add-in-not-working-after/298aff03-c90a-4a2a-b67b-07b6f3c7648c)
We are an organization with over 200 users and are currently using Microsoft Office 2013 (Click-to-run install via Office 365 portal), we have noticed that in Excel when we apply the monthly Office update, the add-in (e.g. Analysis Toolpak) would stop working
with the following error message displayed.
I tried updating from 15.0.4631.1004 to 15.0.4641.1003,
15.0.4641.1003 to 15.0.4649.1004, they all gave the same results.
I have checked the captioned file path and it is indeed missing, I think the update mechanism messed up the add-in somehow, a full re-install would fix it as quick or online repair is not doing the trick.  This is not the only add-in it is affecting
as there are some 3rd party add-ins are affected as well.
Please advise how we can fix this without needing to re-install Microsoft Office.  Thank you!

Answer 1

I don't have 365 or C2R so I can't address your main question, so just a few thoughts which may not be applicable in your setup.
Check the addin manager to see if your addins are listed and ticked. If listed (ticked or not) check the registry to see where the location is written, if ticked look here
HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Excel\Options
and look for keys named OPENx, where x is the order number the addin is loaded
if not "ticked" instead of \Options look in \Add-in-Manager
With a VBA macro or in the VBE's immediate window return
Application.LibraryPath 
Assuming you found a listing in the registry do the paths match, if not look in the .LibraryPath to see if the addins got unloaded there into the subfolder \Analysis
If you find the file(s) try un-installing and reinstalling the addins, but browse to the actual folder don't simply tick. If you can't find the files, copy them (from a different system) to the folder indicated by .LibraryPath. In the addin manager uninstall
them if installed, close the manager, open it again and the addins should be listed, tick to re-install.
You say your other addins don't work, I wonder if some mixup has occurred with what Excel thinks is the default path, but note for other addins the default addins path is returned by app.UserLibraryPath
Are you using a Chinese system?