HxD Hex Editor
Full user review
"Simply the best for free low-level editing"
HxD is awesome! I can't count the number of times I've needed to view or edit a file or disk at the binary level, and every time I've been able to rely on HxD to get the job done. Granted, this isn't a program for which a lot of people will have a need, but for those of us that work with software at a lower level, it's SO nice to be able to turn to HxD and know you'll be able to do what you need to.
I love being able to change the column width and the encoding so easily, and even though I haven't yet had a use to open sections of RAM with HxD, I've got to admit that it's an impressive feature.
None. 100% reliable in my experience.
One example where HxD saved me was when I needed to fix the master boot record of my new MacBook Pro about a year ago (still having buyers remorse over that...) because I was setting it up to do triple booting, and I was able to calculate the partition entries and enter them directly into the boot sector using HxD.
Like I said earlier, where HxD really shines is when working on tasks that a relatively small percentage of computer users will ever even attempt. But because of its solid performance and low memory usage, it's a tool I always make sure to install on every new build of Windows that I install for myself.