2TB HD problem in W7 x64

Just got a brand new WD Black Edition 2TB 3,5 SATA that I installed to relieve those all too slow externals I have, all worked fine, did a full NTFS format in O&O Partition Manager (one single partition, 1,81TB) and started filling it up. Copied some archives, then some more, but when it reached abt. 850gb free it suddenly stopped accepting files!

One file could wait for copying for 1-2 min. when suddenly "cannot write to x:xxx\, remove write protection" popped up! .. This was not the case, so I tried different files from other locations but the same happened. When I tried deleting the half finished directories it just froze up..?? ..waited for ages to delete one or two small files..! Tests and SMART-info all say 100% and error free.

I've checked the web but 2TB shouldn't be a problem - although smaller partitions are better and faster I wanted similar files together as I wouldn't conduct any heavy r/w activity anyway...

Have anyone else encountered this? Is there a general problem with 2tb partitions?

Was a bit absent here, sorry.. I figured it out myself, puzzling enough both O&O Partition Manager, Chkdsk and HD Sentinel failed to detect the error, that actually was my fault entirely. Went to Western Digitals page and downloaded the Lifeguard Tools for this one and did a quick test at first - I/O Cable Error! .. lol! .. checked cabling, and sure enough - Well, cable was ok, but somehow I have managed to mess up a SATA connector on the MB with those d"#¤%&!! cables that lock in place with a metal bracket! Put the disk into another SATA slot and suddenly all was perfect! ...

Anyway, thanks for all replies!