window back up and previous versions....

[icacream]

hello,
does anybody know why I can find previous versions of all the documents which have been backed up, but if I try to get a previous version of the folder which contains those documents, I get this message :

there are no previous versions available

none of my folders, but for C, seem to have previous versions available
I store my documents on a second hd, "D" - no previous version available for D, only for each individual document it contains....

:shock:

 

[icacream]

HELLO...
no one has a clue ?
really ?

the question again : I regularly use window back up and can find previous versions of all my documents but not of the folders.... why ??