Just got a new laptop (mid August 2015) with Windows 10. Other posts here indicate running Audacity (2.1.1) is problematic with Windows 10.
Should I downgrade to / re-install Windows 7? Thanks…
Probably not… Most of the problems are driver related and if your computer came with Windows 10, I assume it came with working Windows 10 drivers for the included audio hardware.
Are you having trouble?
Hi Doug, thanks for posting. I have not attempted to load Audacity 2.1.1 yet. I briefly read through a forum that mentioned Audacity downloading with Windows 10 and several people posted that they had problems getting Audacity to run correctly. Being somewhat technologically impaired, I am hesitant to download Audacity if doing so might mess up my laptop… Audacity’s main web page so far doesn’t include Windows 10 as a system it runs under. However, Wavepad does, maybe I’ll give their free version a look. Any thoughts you have would be appreciated!
Audacity does not yet officially support Windows 10.
Audacity tends to be quite fussy about sound card drivers - it’s like the canary in the mine - if there is a sound card driver problem, Audacity will find it 
Personally I would recommend that before updating to Windows 10, users should check that Windows 10 drivers are available for their computer.
If you have already upgraded to Windows 10 and Audacity is not working correctly, updating the sound card drivers will often fix the problem. See: https://forum.audacityteam.org/t/windows-10-audacity-internal-portaudio-error-or-no-devices/39353/1
If you still can’t get Audacity to run, you can uninstall it and try Audacity 2.0.3 (which seems to be a bit more relaxed about iffy sound card drivers).
http://windows.microsoft.com/en-gb/windows-8/older-programs-compatible-version-windows
http://windows.microsoft.com/en-gb/windows/what-is-program-compatibility
I suspect Audacity can be run in compatibility-mode :
effectively telling your Windows 10 computer , "when you run Audacity, behave as if you’re Windows 7/8 ".
see … http://www.windows10forums.com/articles/compatibility-mode.7/
[ Drivers can also be run in compatibility-mode ]
Thus far, users who have bought a machine that came with Windows 10, as is the case here, have not reported any problems. It depends what the equipment manufacturer has done. Obviously if they were irresponsible and included only Windows 7 audio drivers, Audacity may not work with those drivers.
You won’t break your computer by running Audacity even if it refuses to see your devices.
Audacity can be set in compatibility mode.
But I have seen no evidence yet from anyone who lacked Windows 10 compatible audio drivers that compatibility mode made Audacity 2.1.1 recognize devices.
Gale
If the latest audio-driver software available isn’t compatible with windows 10 , then users may be able to run older driver software via compatibility mode. I can testify that is possible : many moons ago I had to run an old Windows-XP audio-driver on Windows-Vista via compatibility-mode , as a Vista audio-driver with “wave out” didn’t exist.
I am absolutely sure it’s possible, and it would normally be one of the suggestions.
All I am saying is that every time I have suggested it in the current situation with Windows 10 and Audacity 2.1.1, the answer was it made no difference, even if only the built-in sound card was involved.
Gale