Steps to reproduce:

1. Install any SAPI 5 voice and use it with NVDA as your primary speech engine.
2. At some point you will see NVDA crashing.
3. Restarting NVDA will solve this but it can happen again any moment.

Actual behavior:

NVDA will crash at some point when SAPI5 is used as the main synthesizer. This can be fixed by restarting NVDA.

Expected behavior:

NVDA should not crash with SAAPI5, not even when navigating through websites / documents / etc at a fast pace.

NVDA logs, crash dumps and other attachments:

nvda-old.log

System configuration

NVDA installed/portable/running from source:

Installed.

NVDA version:

alpha-36903,3cc61f32 (2025.2.0.36903)

Windows version:

Windows 11 Version 24H2 (build 26200.5651)

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

I am using a Finnish SAPI5 synth. This can be reproduced with any SAPI5 voice, however.

Other information about your system:

Not applicable.

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.

Versions prior to 2025.1 and its alphas worked flawlessly. This is clearly related to the speech engine changes in NVDA 2025.1.

If NVDA add-ons are disabled, is your problem still occurring?

Yes.

Does the issue still occur after you run the COM Registration Fixing Tool in NVDA's tools menu?

Yes.