"Other" is a broad category that includes any files on your system that do not fit into other categories. You're going to need some third-party software to see exactly what files are included. Here are a few utilities that may help sort this out.
Hello - the 'Other' category in the storage bar graph represents all files that are not included in the named categories - take a look at this Discussion for a more thorough explanation and suggestions to reduce its size.
If not already on your computer, you might want to obtain a copy of Onyx HERE (OS X version specific, so download the right one) - this app can 'clean out' a lot of caches and unneeded files and probably would make a 'dent' in your 'Other' category - do a before and after comparison.
Also, I hope that you have backups of your computer, e.g. Time Machine and/or a cloning program (I use Carbon Copy Cloner) - and don't just start deleting files if you do not understand their purpose - you might end up disabling your computer. Good luck. Dave
Best way to free up space on that machine is to replace the hard drive with a larger one and then transfer everything over. There are 1TB drives that fit in your machine. Check them out at Other World Computing.
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