In reply to a question about how publishers protect their software, and how that affects your backups:
 
How?
Well,  they keep that stuff close to the vest, but here are the general ways:
The MAC address of your machine;
The ethernet address of your machine;
The GUID of your hard drive;
The size of your hard drive partition;
The serial number of your machine;
invisible files (often inside other invisible directories);
invisible files kept at a specific block (track and sector) of a hard drive;
number of times you’ve authorized the software as kept on their servers (often in conjunction with one of the above);
other hardware conditions;
dongles;
phase of the moon…. (meaning all the other stuff I don’t know about, or stuff I forgot.)
More than one of the above.
 
So how do you back up a drive with that kind of software on it?
 
Does one use a block-copier, such as CopyCatX (CCX) or Carbon Copy Cloner (CCC), or does one use a file-cloner such as SuperDuper (SD)?
 
A block copier will make a “perfect” copy of one drive to the next. (Actually, while I do use CCX in many cases, I also have a hardware device that will let me plug in to bare drives, and it will block copy one to the other unattended.)
 
Now think about SuperDuper: it will make a clone of a drive’s files, hidden, invisible, symbolic links etc, but those files will be in different physical places on the destination drive, vis-a-vis their location on the source drive. (That’s why you can SD clone to a blank destination drive and it’s the same thing as defragmenting and optimizing.)
 
SO…. depending on the type of protection the software developer has used, a block copy (CopyCatX) may or may not be most suitable… or irrelevant.
 
If the protection is the GUID of the drive, nothing will help: if you forgot to (or couldn’t) deactivate first, you’re up a creek.
If you replaced the motherboard, you’re also SOL.
Change the partition size? Doomed.
 
My guesses: Windows checks partition size (among other things). I suspect Adobe uses the server/GUID/Serial number technique. Office uses the server authorization check and drive UID. MOTU uses invisible files. etc.
 
I use SuperDuper to make a rotating set of clones. Recently I had cause to use one because my little Raptor drive ended up with a serious problem. I was asked why I did not use CCC to block copy the info back from the clone and used a SD clone-back instead.
 
Why would one NOT use CCX to clone back for several reasons:
1) the destination drive is smaller than the source;
2) if the clone had the issue as well (due to when it was copied) I’d just be wasting my time, so the SD “sync” was a “cheap” test for a fix;
3) the source (the SD clone) has all its files in different physical places than the original, and I didn’t want to break anything that used that technique;
4) and I didn’t swap the drives because the GUID of the drive is (by definition) different;
5) phase of the moon.
 
(I would have swapped drives had the “sync” not solved the problem.)
 
Finally, and only FWIW, when I first ready a drive to be used as a SD clone destination, (and it’s the boot drive I’m cloning) I -do- use CopyCatX (or my dup machine) to make a block copy, just so that at least some of those protected apps will work (although, as seen above, some will still require jumping through hoops regardless.)