Problem with Converting from Endnote 7 to X2 - missing pdfs

I have just tried to upgrade (convert)  two large libraries (>20,000 records each) from Endnote 7 (7.0.0) to Endnote X2. In both cases, the attached pdf and word files that were linked via the Image field in version 7 fail to become available in the converted libraries. A symbol (tick) appears, where it should, in the displayed Figure field when browsing, but there is nothing in the field when the record is opened. (I have copied the .data files with the library files).

I have also tried converting the Endnote 7 libraries first to Version X- but that also fails in the same way.

However a smaller (c. 400 records) library compiled in Endnote 7 during 2008, also with many attached pdf files, did convert successfully first through Version X and then from X to X2.

Am I missing something obvious?

I would be most grateful for any suggestions.Thanks in advance.

Problem now solved. After multiple unsuccessfull attempts, and eventually using a test library with only a single record which was successful, the conversion of libraries from EndNote 7 to EndNote X2 is now working fine with all .pdfs etc accessible. Not sure what caused the early failures.