Cannot save file

Hello I have a problem in saving files in Mathematica. I can't save not only notebooks but also figures. When I choose to save the notebook it open a window that says:

Mathematica could not find enough disk space to save the file C:\Users\Διονύσης\Documents\science\mathematica\Untitled-1.nb. The file was left unchanged. The disk is full, or if you are using a file server you may have reached your disk space quota.

Although I have notebook saved from a friend. I can save on it. When I want to use it i simply copy-paste it, delete the code, wright mine and then I can save it without any problem. But still I cannot save figures. To save them I can only copy-paste them to Word from where I can save them as figures.

If anyone could tell me the source of my problem it would be helpfull! Thank you very much!

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I think the problem is that there is a greek folder in the path, try saving on the root of the drive, c:\, or to another drive to see if this is the problem. –  Spawn1701D Apr 22 '13 at 9:29
That was the problem! Thank you very much for your help! –  2island Apr 22 '13 at 9:43
Τίποτα! Μάλλον μονο οι Έλληνες το έχουν αυτο το πρόβλημα ;) –  Spawn1701D Apr 22 '13 at 9:48
@OleksandrR. Sorry, I didn't realize it was you who added the bugs tag (I should pay more attention... I thought it was posted like that). This is a common problem on Windows: many programs don't support Unicode paths. If the OP's locale is set to Greek, it should work, otherwise there's a chance it won't.(It was the same for me: I can't use őű in path names if I have the locale set to English in WinXP, and I also can't use Chinese characters.Once I got into trouble because I created a chinese-named dropbox folder on a Chinese computer, and I couldn't open Mathematica files within it on my own –  Szabolcs Apr 22 '13 at 16:30
@OleksandrR. Mathematica uses the standard library for file APIs. Whether CreateFileA or CreateFileW gets called is an implementational detail of the VC++ standard library. It is true that we are using the non-widechar version of the standard library file functions, which is, of course, the cause of the problem. In answer as to why on earth we would still, in 2013, be doing this, I can only say that it's something I certainly would have done had I more resources, but I'm always forced to choose between shipping one thing or another (and that choice has many outside influences). –  John Fultz Apr 22 '13 at 18:43