The maximum number of files and folders available on a hard drive is
roughly limited to about 4.3 billion total, with a 64,000 file limit. If
you're having a problem opening the files, it may be related to Finder
memory allocation instead.
Do this:
1) Do Get Info on the Finder. (In the Finder, select the Finder file, then
choose Get Info from the File menu.)
2) Increase the Application Memory Size by 100K.
3) If that doesn't work, increase the memory allocation by another 100K.