HD-CE500LU2 Windows XP cannot copy some files

[peterj.13.07]

I cannot explain this behaviour. I have a HD-CE500LU2 NAS connected to a Windows XP (current updates). This setup has been working for quite some time & I've not noticed this behaviour before. I have a folder containing a number of files. When I copy the folder to the NAS, some of the files are not copied. All files have the same permissions and ownership (no visible differneces under file properties). The NAS has plenty of capacity available. The files are not big (between 100kB and 200kB). I can copy these files to an external USB hard drive OK. When I use windows file manager to copy the files (drag & drop, individually, or as a set) to the NAS, no errors are reported, but the ("problem") files are not copied to the NAS. If I use a DOS command window, the copy produces a 0 size file (for the "problem" files) on the NAS (the other files are copied OK). I have tried renaming the (original) files with no effect. I can zip the files, copy the zip file to the NAS and extract the files on the NAS. I can also not copy the zip file to the NAS and simply extract the files into the target folder on the NAS, but I cannot copy them directly from a local drive to the NAS. Any ideas? This is driving be around the twist!

[TheSidewinder]

That sounds vaguely like your antivirus/firewall may be interfering, even given your description of being able to copy the file(s) elsewhere.

Long shot perhaps, but disable both of those and try again?

[peterj.13.07]

I did think of the virus scanner & did try this after disabling it - same result. Can't see it being the firewall - some files copy successfully. Noticed a typo in the original post - I can extract zipped up versions of the files directly to the NAS - but I cannot copy them directly. I'd expect that if it was the virus scanner (btw, I'm using AVG & it is up to date), I'd not be able copy the files to an external USB HDD or any other drive (this works fine). The virus scanner does not report any issues. One common point - all problem files (at least so far) are PDF's created with the PDF 995 printer driver (I haven't encountered any other issues with this driver - files open fine in adobe reader, copy OK to other drives, etc.). Only issue I have is copying files directly to the NAS drive from a local drive. I can copy the problem files directly from the NAS drive back to a local drive. Still puzzled.