1.txt.zip
nvda-old.log

Steps to reproduce:

1. Download the attached test sample: 1.txt.zip and remove the .zip extension;
2. Or use the following python code to generate a document identical to the test sample

with open(r'd:1.txt', 'w', encoding = 'utf-8') as f:
    f.write('[I 211209 00:10:40 web:2239] 200 GET / (::1) 335.00ms\n' * 300000)

3. Use Windows notepad to open 1.txt;
4. Keep holding down the down arrow;
5. If you configure "Play a sound for logged errors" to yes you will hear the error sound and nvda will exit.

Actual behavior:

nvda exit

p.s. In the same situation narrator works fine.

Expected behavior:

nvda doesn't exit and can report the content of the line the cursor is on

System configuration

NVDA installed/portable/running from source:

installed and portable

NVDA version:

2021.3.1 and Alpha

Windows version:

Windows 10 21H2 (x64) build 19044.1526

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

None

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.

No

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