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Messy Backup

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I am using Windows 10 Pro and when the software creats a backup it is so fragmented that it takes over two hours to defrag it.  This is on my slave drive copy of the backup.  Is it always so messy?

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It's really going to depend on your destination disk, how much space is left on it, how many other files exist on it and the size of the backup file.  If your backup disk already has other content on it and you're trying to cram a single large file on the drive, Windows (not Acrnis) is going to write the blocks of data on the drive however it needs to to be able to fit it on the disk.  

Compressed data also results in higher fragmentation:

http://superuser.com/questions/693275/avoiding-extreme-fragmentation-of…

Reading the article on Wikipedia about NTFS compression:

Files are compressed in 16-cluster chunks. With 4 kB clusters, files are compressed in 64 kB chunks. If the compression reduces 64 kB of data to 60 kB or less, NTFS treats the unneeded 4 kB pages like empty sparse file clusters—they are not written.

This allows for reasonable random-access times - the OS just has to follow the chain of fragments.

However, large compressible files become highly fragmented since every chunk < 64KB becomes a fragment.