Have to defrag twice

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Hi, new here so please don't be too harsh. Could anyone enlighten me as to why I have to defragment twice since version 1.10 came out? when I defragment the first time it says that certain files could not be defragmented because there is not enough free disk space. However having 772Gb of free space and the file sizes ranging from 100Kb to 3Gb, I don't quite think that its true. The second time I defrag though everthing just clears 0.00% file fragmentation.

 

Any help would be appreciated thank you

 

Windows Vista Ultament SP1 32-bit

IO-Bit version 1.10

(Skip files over 1Gb not enabled)