Next, download and install Flash Player and see if this fixes the missing issue. If not, follow Adobe's advice: run the Flash Player uninstall tool (see the top of this page).Restart your computer (do not skip this step) and try running the standalone installation file again.If I add that user to the administrators group and have them run the REGSVR32 command it works fine for them.Unfortunately it really isn't feasible for me to allow all users to be administrators on their machines.Suggested solutions that are not likely to fix the issue, and why Solution to all of the issues: download the standalone Flash Player installer which includes the file (links are at the top of this page).
OCX in c:\Windows\Sys WOW64\ (note, in the browser window, you need to change the file type from "dll" to "OCX" (or "all")) Daniel Alexander Karr (refer post further below) has kindly shared a script he wrote to do steps 1&2 automatically (Attention, needs to be run AS ADDMINISTRATOR).OCX) (Note: this step seems optional as I have checked that doing only step 1 & 3 made the workbook work again.But it feels like the right thing to do) 3) In the in the Excel workbook VBA project, Microsoft Windows Common Controls 6.0 (Service Pack 6) needs to be de-referenced and re-referenced.You can check if this OCX is doing something for non-admin user by using Process Monitor tool and check for ACCESS_DENIED errors.
In case if your OCX doesn't do anything under admin account, what you can try to do is to register you OCX under HKEY_CURRENT_USER lever by using Reg Svr Ex tool.
EDITED ONCE SOLUTION WAS FOUND: I have added a Treeview Active X Control to one of our spreadsheet, using Microsoft Windows Common Controls 6.0 (Service Pack 6), i.e. OCX which lives in c:\Windows\Sys WOW64\ KB2881029 (Security Update for Microsoft Office 2010 32-Bit Edition) (MS16-004), pushed out from Microsoft on the 15/01/2016 (or thereabout), installs a new MSCOMCTL.