Steps to reproduce:

1. o to the control panel
2. click on regional settings
3. go to the administrative tab.
4. go to the language for non unicode programs settings button
5. check the checkbox use utf-8 for the language support in all the world
6. when prompted, restart your computer.
7. when restarted, try to install any NVDA add-on
   It doesn't matter, which NVDA add-on you want to install

Actual behavior:

nvda produces this error in the log and fails with installation
INFO - core.main (15:24:16.638):
NVDA initialized
ERROR - gui.addonGui.AddonsDialog.installAddon (15:24:43.007):
Error installing  addon bundle from C:\BrailleExtender\BrailleExtender-dev-18.08.06-151459.nvda-addon
Traceback (most recent call last):
  File "gui\addonGui.pyc", line 160, in installAddon
  File "gui_init_.pyc", line 869, in init
LookupError: unknown encoding: cp65001

Expected behavior:

add-on wshould install normally

System configuration:

windows 10 17713 russian and windows 10 1806 17134 polish, locale polish, regional settings polish or russian locale with regional set to croatian

NVDA Installed/portable/running from source:

installed

NVDA version:

alpha-15781,d58e1cd4

Windows version:

10.0.17713.1002 or 10.0.17134 april update

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

n/a

Other information about your system:

n/a

Other questions:

Does the issue still occur after restarting your PC?

yes, when the unicode support is enabled

Have you tried any other versions of NVDA?

no, but other versions may fail.