I originally got a Harmony one and found that whenever I tried to learn functions from other remotes I would get poor or no ir signal detected. I then would vary the distance or angle from the original remote(s) to the Harmony. The remote would unexpectedly say Key detected and to press one more time, and of course, the signal would be either copied weakly or not at all! I have to say that I have been using learning remote of various brands for years, so I'm not new to this. I checked batteries, changed usb cords, computers both Vista and XP Pro, turned off lights, removed power strip from laptop. I called tech support, they thought it was a bad ir input plug on the Harmon one. I returned the remote to Amazon and got a Harmony 880 since the tech guy confided that the 880 was more stable. Well I got the 880, and you guessed it...same problem. Called level two support and he asked me to try to copy the codes in Raw. The tech stated that since the remote learned some of the codes that the problem was in My house. I just don't know what to do now, I really liked the Harmony one but found that the screen was too sensitive (yes I do know that the sensitivity can be lessened, but it still was too sensitive). I really think that maybe the problem is in the software. I feel that I'm the only person with this problem.

You can get IR interference/jamming from nearby sources like compact fluorescent lights, LCD/Plasmas displays, etc.

I haven't seen the issue happen on the 880, but there are many other users who have experienced the same learning ir issue on the H1. And there are several posts on both the Harmony forum and another a/v forum. The solution that worked best for me on my laptop is to move the computer with the remote into another room away from all other electronic devices and learn ir there. The solution I've read for desktop PC users is to plug the USB directly into the PC (not into a hub), shut down devices that are not needed, and pull the connected remote as far away as the cable will allow. By the posts I've read, this also seems to work fine.
Word from Logitech is that the H1 hardware is overly-sensitive to other electronic equipment.
,R

It's happening all the time. I sent my first One back and took another as replacement, but neither would learn at all, anywhere, in any surroundings.
Do you really need the learning though? Not having it made me realise that I could get the One to do everything I wanted without it.

Thanks for the input! Most of the learning codes that I need and have managed to have copied are discreet and are custom codes. I've never had any problems copying codes using my Home Theater MX series. I bought the Harmony due to the high user reviews posted and slim design. I have managed to learn 90% of what I need the most but it has taken quite a long time and effort. Now I'm working on Sequencing commands, five commands max at a time is a joke! As I said before, I really did like the feel of the Harmony one, but was afraid that it was broken.

It wasn't broken, it was of those that won't learn - some will, some won't!
I agree 5 commands to a sequence is too few, but like learning I find little need for them.
Anything that takes more than 5 is usually needed only once in an Activity, so it can be set up as a series of additional commands when entering and leaving the Activity.
Despite its faults the One has to be the best of the series so far.