Steps to reproduce:

1. Enable "use UI Automation to access the Windows Console" from advanced preferences.

2. Run cmd.

3. Start a python interpreter: python.

4. Run:

   for i in range(100000):
   print("test")

Actual behavior:

"test" is read for a few seconds, then all UIA applications become completely inaccessible until NVDA is restarted.

Expected behavior:

Output stops for a few seconds, then UIA recovers.

Context

I also tried disabling UIA connection recovery and event coalescing with the following in the NVDA Python console:

import UIAHandler
UIAHandler.handler.clientObject.CoalesceEvents = 0
UIAHandler.handler.clientObject.ConnectionRecoveryBehavior = 0

After UIA dies, running uiaHandler.terminate() and UIAHandler.initialize() does not restart UIA functionality. I'm not sure how to detect when UIA breaks or how to restart it once it does.

System configuration

NVDA installed/portable/running from source:

Installed and source.

NVDA version:

Latest master (b38776a).

Windows version:

Windows 10 21H1 insider.

Name and version of other software in use when reproducing the issue:

Windows Console

Other information about your system:

Other questions

Does the issue still occur after restarting your computer?

Yes.

Have you tried any other versions of NVDA? If so, please report their behaviors.

2019.2.1, 2019.3, 2020.1 (all same result).

If addons are disabled, is your problem still occuring?

Yes.

Did you try to run the COM registry fixing tool in NVDA menu / tools?

Not applicable.