I record with audacity on a Toshiba laptop with Windows 7, then I edit on an old e-Machine with Windows 7. When playing back in editing, I frequently get “Error opening sound device. Try changing the audio host, playback device and the project sample rate.”
Note that I got this a lot on the previous version, and I updated to Audacity 2.1.3 last week and I still get it. My STANDARD way of dealing with it is to hit “OK” on the error message, and then hit “Play” AGAIN, & the thing will frequently play. But sometimes it doesn’t. So then I hit OK>>Play, several times, and eventually it will work. Some days it barely shows the error message at all; other days I just have to click a lot. I’m getting old, and I worry that this is contributing to arthritis in my left thumb. But I digress…
So I checked audacityteam.org which told me how to:
check the sample rate(it’s at 44100),
turn off the Software Playthrough and the Overdub(only one of which was on, but OK, turned them off)
and a bunch of other stuff about setting my playback device,
…so I’m trying to work my way down this checklist, but I guess my question is: If I’ve got some setting wrong, why does just hitting “OK>>Play” multiple times, actually WORK?(sometimes)
multiple times, actually WORK?
Because you have a ratty playback device? What is the playback device? Is it a USB device or USB connected? If it is USB, are you going through a USB Hub?
Sometimes Audacity will freak if it can’t find your record device, too. Check that’s not pointing to a ratty or badly connected device.
http://manual.audacityteam.org/man/device_toolbar.html
You should probably make sure Windows and Audacity are pointing at the same things. First level maintenance is shut down the machine and unplug and replug everything several times.
Sometimes on larger machines, the connections on the front are less stable and are just extensions of the more reliable connections on the rear.
Koz
OK, I messed with a lot of stuff, and now it’s working… 
It seems that for the last couple of days, “Windows Direct Sound” has been working better as a host, than MME was(although MME did work, at least intermittently, for a long time.)
Yeah, I’m going with “ratty” something. This computer is at least 10 yrs old. There’s no microphone connected; this is the machine I use just for editing. So that’s never been an issue.
But I do have my headphones plugged into the front, simply because I couldn’t get the thing to DETECT them, if I plugged them in the rear.
Assuming you record or play using the built-in sound device, do either of these machines actually have correct audio drivers for the built-in audio device?
For example the Toshiba should have the latest audio drivers for Windows 7 from the Toshiba site (64-bit drivers if you have 64-bit Windows). See http://wiki.audacityteam.org/wiki/Updating_Sound_Device_Drivers.
Gale