I have about 65 GB free on my drive. I want to defragment a couple of times and then partition about 54 GB off for other uses - I know you are supposed to back up but I do not have options for that right now. How likely is it that this will erase some data?How likely will changing partitions erase data?In order to take your 65Gb drive and divide it off into 2 partions... Its not going to happen. In order to create 2 partitions, you need to start from scratch, which is make 1 54Gb partition and a 11Gb partition. Your entire drive needs to be divided, which means you need to start fromt he beginning. You need to delete all your partitions before creating a 2nd one, which means all data is wiped...
The only exception to the rule, that I know of, is when you use a program called Partition Magic. Its suppose to be able to allow you to create, add/delete partitions on the fly without any consequences... Whether that is 100% true, I'm not sure. Google it.How likely will changing partitions erase data?Well, in theory, you can resize non-destructively, but there's always a very slim chance that your data will somehow get corrupted in the resized partition. I would wait until you have a backup option.
A GParted live CD can help you resize the partition and create a new one.
Why do you want to create a new partition anyway?How likely will changing partitions erase data?You will not leave enough to comfortably run the machine. Defrag does NOT free disk space. The most you should take would be about 30 GB.How likely will changing partitions erase data?When you partition a drive you will loose all data.
Because it has to be formatted to use windows boot menu
