This article is from the Computer Viruses FAQ, by Nick FitzGerald n.fitzgerald@csc.canterbury.ac.nz with numerous contributions by others.
Probably not. This happens now and then, when something sets the
"cluster number" field of a subdirectory to the same cluster as an upper-
level (usually the root) directory. On PCs the /F parameter of CHKDSK
should be able to "fix" this (as should many other popular disk-repair
programs), usually by removing the offending directory. *Don't* erase
any of the "replicated" files in the "odd" directory, since that will
erase the "copy" in the root as well (these are not really copies at
all; just a second pointers to the same files).
 
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