Sorry. I’m using 2.4.1 currently. I’ve tried older versions with the same result. I’m recording drums thru my Presonus AudioBox iTwo USB interface into my Lenovo laptop with Win10. All the sound settings were set to default. I’ve used this interface (and my Behringer U-Phoria UM2, but it combines the two inputs into a mono mix) for months without any problems. I’m getting sound going into Audacity just fine. It just won’t let me record. I press the button and it just stalls.
Behringer U-Phoria UM2, but it combines the two inputs into a mono mix)
Let’s take that one first. If you mount a UM2 stereo in Audacity, it will put the live microphone on the left and the instrument on the right, and record it that way. If you have UM2 Direct Monitor selected, the headphones will present a mono mix. Technically, they’re lying to you, but that turns out to be handy if you’re trying to sing and play a musical instrument at the same time. You really don’t want your voice showing up just in your left ear and the guitar in your right. That’s disorienting.
If you play something stereo to the UM2 (existing recording, backing track) that does show up correctly in the headphones left to right.
This is a handy stereo test sound file.
If you mount the UM2 Mono instead of stereo, it will dump the instrument and record microphone-only as mono. Oddly, both microphone and instrument will stay live in your headphones—in mono-mix—while you’re doing this. Turn the instrument volume control down to temporarily get rid of this effect.
In all cases you should use the UM2 flashing red and green lights as volume guide. The interface may overload at a different volume than Audacity. If you avoid red lights, you can fix it all in post.
Koz
I’m working up an overdubbing test process since so many people have trouble with this. We should note that in proper overdubbing, the computer has to play sounds to you absolutely perfectly at the exact same time that it’s perfectly recording your new performance.
That’s not easy. Sound errors in either recording or playback or both can appear.
I need to drop for a while.
Koz
I’ll give the UM2 another shot, but I use the Prosonus because they have dual XLR inputs.
The issue is not related to the interface. I can get sound to record, but both record and playback cursors will just freeze when I press record.
I can get sound to record, but both record and playback cursors will just freeze when I press record.
Can you take that again and use different words.
Simple recording works but overdubbing fails? Not unusual. Overdubbing is the first time record and playback both have to work at once. You can get a frozen cursor when the data freezes, but the interface “seems” to be OK.
I like the UM2 because I have one and I can track exactly what happens under different conditions. For example, I don’t think there are any setups where it will record a mono mix. If that’s what you got, then there’s something serious wrong right there.
Koz
Just a shot in the dark. You might check that your project and track sample rates match with those of the interface box. For example, you might have Audacity set to 44.1kHz, with the interface box set at 48kHz or even 96kHz. Good luck. 
Good luck.
And post back if you find it. We’re also tracking an apparent failure of multiple Windows users all at about the same time.
Koz
What was the solution to this two years ago? I am having this issue now with the latest version of Audacity and Windows 10 on a Roland Rubix 44.
Frequently problems that appear on the surface to be exactly the same are, in fact, exactly different.
Please describe your problem in detail as to what exactly is your problem and which of the remedies that have been suggested have you tried?
Perhaps you will find it easier and less confusing to start a new topic. 