TeamViewer is free for personal use only, and it uses certain rules to try and determine if someone is violating those terms. If they suspect your use is not personal, you will get a message saying that they suspect, or even think they're sure, that you're using TeamViewer commercially. From that moment on, the software will be severely restricted by closing every session after about 10 seconds.

After years of using TeamViewer to access my home desktop while I'm ouf of the house, I somehow managed to trigger this. Factors that people suggest can lead to the commercial use suspicion are running the program on a Server edition of Windows, in an Active Directory domain, or regularly opening a lot of sessions to many different computers. None of this was the case for me. What I suspect triggered it in my case, was a high number of reconnections. I had an issue with my computer which I couldn't wait to get home to try and figure out. I needed to reboot the system often to do that, every time closing and re-opening the TeamViewer session. The day after, my account was locked.

TeamViewer offer a way to ask them to look at your case in person, and determine if you've been falsely flagged. It says it will take around a week. After I did that, I got back an e-mail telling me that looking at my usage data, they were unable to determine that my usage was non-commercial. Which, given my usage pattern, can only mean that it's a standard reply and they didn't really look at it. It did, however, include a form for me to fill out and sign to attest my personal use. That's been about three weeks ago and I haven't heard back.

I'm writing this just to inform people about this possibility of being locked down, and the process involved. It's not meant as a complaint towards TeamViewer. They do offer a service for free, and the fact that they even offer an appeal process is very commendable. And I understand that they can't spend too many resources on handling those requests, since they are from people who are not likely to become paying customers in the near future.

I will add, though, that I might have considered paying for a license even if my use is strictly non-commercial, just because I enjoy the service and I would be fine with supporting it financially. However, even their most basic license is so expensive that it's clearly aimed at professionals who use remote access for customer service. It's not reasonable to pay more than $400 a year for an individual just wanting to remotely control their computer.

In the meantime, I have switched to the alternative AnyDesk software, which is also free for personal use. They don't seem to have such an automated suspicion system, and work more by offering licensed users additonal features that are helpful for professional use. Their basic license is also less than a fifth of the price of TeamViewer's reaching a price range that might be justifiable even for personal use.

Update, November 15: It's now almost three months ago that I initiated the appeal process, and I haven't heard back from the people at TeamViewer. Again, this is only informational – I'm not upset at them, as it's a free service and it's their right to refuse to offer it to me. In the meanwhile, I've grown very fond of AnyDesk. It's an excellent software and service, so I doubt I'd even re-install TeamViewer if they replied to me at this point.

Update 2019: A few months back I tried using TeamViewer again and the block seems to have been lifted. I don't know when that might have happened since, as I mentioned, I'm generally using AnyDesk now when I need remote access. For the same reason I also didn't use TeamViewer for multiple, or longer, connections anymore, but it did let me access my computer for a few minutes, which was not the case in the "banned" state. I checked my e-mail and spam filter archives but couldn't find any further messages from TeamViewer, so if they did unblock me due to my request, they didn't actively notify me.

[Edited by Anamon, November 15]

[Edited by Anamon, June 03]

Ever since the breach to TeamViewer's security, and how long it took them to acknowledge the problem, and how they even handled the problem once they finally did acknowledge it, I've been trying to find an alternative.

I may just bite the bullet and pay LogMeIn for a personal account.
VNC is super insecure as is RDP.
I've used NoMachine in the past on my Linux boxes and it works smoothly once configured - but I've never ran it on my Windows PC's.
The other problem is if I am on the road and my wife tells me there is a problem, remoting in isn't so easy without opening a bunch of ports on your router/firewalls.

now they are basically forcing you to pay, i don't like it anymore, i'll start looking for a good alternative that has a free version. I think they are taking advantage of the users and the fact that it has some many right now.

i have used this several times and the only thing that i don't like is that is really slow sometimes. That should be improved

Free alternative to TeamViewer. Configure private ID server for corporate using.

I have used TeamViewer for years to help family and friends with their technical issues.
Easy to use; good for file transfers.

easy to use for remote assistance, quick and useful

its is very good for team especially for VA

it allows me to fix issues on my friends pc from home or office in a snap

i think this works fine as long as you just need little things, i have used it for fixing some issues in other computers but just very quick stuff

i think this is very useful, specially when you are trying to help someone out of reach.

i think it is worth it, is very simple and allows you to help anyone without having to even touch their computer.

i use this all the time and works fine for me, very helpful

i haven't got a problem with it, i use it all the time and works fine.