VBA unavailable from Office programs

I recently reinstalled Windows 10, Avira Free Antivirus v. 15.0.44.142, and Office Professional Plus 2010. Before the reinstallation, this combination of applications worked fine.

Now, when I try to open the VBA IDE from a new Word document, I get the following message:

Word has encountered a problem.

There is a problem saving the file.

with some possible causes listed underneath, such as missing disk space, low RAM, or missing permissions; none of which are relevant.

The only thing that might be relevant is:

This error can also occur if the computer is running a version of antivirus software that is incompatible with the Microsoft Office or must be updated.

As noted, I am running Avira Free Antivirus, and AFAICT the antivirus is updated. I tried opening the VBA IDE while Avira real-time protection was turned off, but without success.

Once I dismiss the message, the VBA IDE window opens, but there is no available project, and most of the menu items are disabled.

Saving a document with the .docm extension before opening the VBA IDE doesn't help.

There are comparable odd results when trying to open the VBA IDE from other applications:

• Excel lists three projects Project1, Project2 and Project3, but without the usual tree of objects underneath each project -- class modules, standard modules etc -- and without the ThisWorkbook node.


• PowerPoint does the same as Word -- no project at all -- but without any error.

I've tried uninstalling and reinstalling VBA via the Office installer.

Security settings are set to disable macros with a warning. IIRC the old behavior was to disable macros unless I explicitly allowed them for the specific document. Trust the object model for each application is checked.

I've looked for a setting to control this in Avira, with no success.

The registry doesn't contain the VBAOff key described here.

How can I enable VBA for the Office applications?

NB. The previous installation wasn't a clean install of Windows 10; it was first Windows 8, then 8.1, then 10.

Things I have tried before opening the VBA editor:

• Repair Office


• Uninstall and reinstall Office, then manually install Office 2010 SP2


• Windows update (only found Office updates after the aforemnetioned manual installation)


• Running Word with administrator permissions


• Enable all macros selected from the Trust Center


• Deleting the Normal.dotm template and allowing Word to recreate it


• Uninstalling Office, running the "Clean Office uninstall" tool referenced by @harrymc in the comments, and reinstalling Office


• Adding Outlook (which was previously not installed)


• Turning off UAC (before starting Word)


• Booting in Safe Mode -- I was unable to start Word; Word wasn't recognized as activated


• Setting HKLM\SYSTEM\CurrentControlSet\Control\FileSystem LongPathsEnabled = 1, and rebooting

---

Looking at the Event Viewer, I didn't find anything in System, Application or Security (all under Windows Logs). The only thing I did find was the following event in Applications and Services Logs -> Microsoft Office Alerts every time I try to open the VBA editor in Word on a new document:

Log Name:      OAlerts
Source:        Microsoft Office 14 Alerts
Date:          07/03/2019 20:49:42
Event ID:      300
Task Category: None
Level:         Information
Keywords:      Classic
User:          N/A
Description:
Microsoft Word
Word has encountered a problem.
P1: 200815
P2: 14.0.7015.1000
P3: 5v59
P4: 0x80070002
Event Xml:

  
    
    300
    4
    0
    0x80000000000000
    
    120
    OAlerts
    
  
  
    Microsoft Word
    Word has encountered a problem.
    200815
    14.0.7015.1000
    5v59
    0x80070002
  

There is no similar event when opening the editor in Excel or PowerPoint.

---

Using Sysinternals ProcMon, capturing only while trying to open the VBA editor from Word, and filtering the results for Process Name = "WINWORD.EXE" and excluding SUCCESS, BUFFER OVERFLOW and NAME NOT FOUND from Result, I found the following:

RegOpenKey         ACCESS DENIED
      HKLM\Software\WOW6432Node\Microsoft\VBA
CreateFileMapping  FILE LOCKED WITH READERS
      C:\Program Files (x86)\Common Files\microsoft shared\VBA\VBA7\VBE7.DLL
CreateFileMapping  FILE LOCKED WITH READERS
      C:\Program Files (x86)\Common Files\microsoft shared\VBA\VBA6\VBE6EXT.OLB

The FILE LOCKED WITH READERS repeats a number of times.

But on further investigation, I see that later reads from the same registry key (HKLM\Software\WOW6432Node\Microsoft\VBA) succeed. Also, the CreateFileMapping is using the long name of the path; which is immediately followed by a successful CreateFileMapping using the DOS name, e.g. C:\PROGRA~2\COMMON~1\MICROS~1\VBA\VBA7\VBE7.DLL.