Users who are not administrators can deactivate any COM add-in on an Office 2010 application.
To resolve this issue, apply the following update:
2817377 Description of the Office 2010 hotfix package (Mso-x-none.msp): June 11, 2013
Registry key information
Follow the steps in this section carefully. Serious problems might occur if you modify the registry incorrectly. Before you modify it, back up the registry for restoration in case problems occur.
After you install the hotfix package, follow these steps to enable the hotfix:
Click Start, click Run, type regedit in the Open box, and then click OK.
Locate and then select the following registry subkey:
HKEY_LOCAL_MACHINE\Software\Microsoft\Office\14.0\Common\Security\Note If you install the x86 version of Office 2010 on a computer that has the x64 version of Windows 8 installed, the registry subkey is located in the following location:
On the Edit menu, point to New, and then click DWORD Value.
Type DisableLMAddinOverwrite, and then press Enter.
In the Details pane, right-click DisableLMAddinOverwrite, and then click Modify.
In the Value data box, type 1, and then click OK.
Exit Registry Editor.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.