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Since this week I have noticed that my XP machine is showing as offline in my TV account,even though TV13 (latest version) is starting fine on XP machine.Also login to account works fine on this XP machine.
Same thing happened to me yesterday, with 5 PCs all running Teamviewer v8. I noticed that after re-setting up Unattended Access, a PC started showing Online again. I had to do this at the PC itself; I couldn't do it remotely.
Thanks a lot, this trick worked fine in latest version 13.