[Sprint HTC One (M7)] coal686:
Please read and understand the guide and accompanying links in their entirety before beginning.​

XDA and I am not responsible for anything you do to your phone.​

This guide should work for anyone trying to RUU their phone, but let me give you my background on this first.

While trying to run an RUU to reset my phone, I kept running into an issue: "htc_fastboot.exe has stopped working". I could get my phone to restart, but the RUU would not run successfully. I searched this site and the internet for an answer, but could not find anything that worked for me. Also, a lot of people in Q&A tend to have issues getting the RUU to work. That's why I'm writing this guide. Hopefully someone who is having trouble will search and stumble across it. I tried everything I could find - Windows 7, 8.1, different RUUs, etc and this is how I finally fixed it. I am s-off by the way and did this in Windows 8.1 Update so the guide is written from that perspective.

Steps:

1. Make sure that your computer can see your phone when you boot into fastboot. It should say Fastboot in red that changes to Fastboot USB when plugged into your computer. There are guides that help with this, so I'm not going to go into much detail. Basically you install HTC Sync to your computer and then uninstall it but leave the drivers.

2. Get a copy of fastboot and ADB. The easiest way is to get the SDK from Google (tools only) as it also includes drivers, but you can get just fastboot and adb from here (I did not use this tool personally).

3. To verify that your phone and computer are talking, open a command prompt window (I always open as administrator) and go to the folder that contains fastboot. Type "fastboot devices" (no quotes) and it should list your phone. If it does not, something did not work right with steps 1 and 2.

4. If you are s-off, you do not need to lock the bootloader. If you are s-on, then you need to lock the bootloader by typing "fastboot oem lock" (again, no quotes).

5. Download the Full Firmware from RUU here. While you're there, get the RUU as well. Make sure to get the one that is not decrypted (first link). Copy both into the folder with fastboot.

6. Flash the firmware file using fastboot following the directions in the OP from where you got it. To summarize, rename the firmware zip file to firmware.zip. Then at a command prompt, type "fastboot oem rebootRUU". When the phone shows a black screen that says HTC, type "fastboot flash zip firmware.zip". The command prompt window will show a bunch of stuff as it does its thing. When you get back to the command prompt, it's finished. At this point, type "fastboot reboot-bootloader" to restart back into the (hopefully now stock) bootloader. Personally, I had to repeat the last command again because it failed the first time.

7. At this point, you should be in the stock hboot. It should say fastboot USB in red. Now time to RUU.

8. The current RUU is an exe so run the RUU you download before (if you have a zip file, unzip the RUU and run ARUWizard.exe). I personally ran it as an administrator just to make sure limited privileges didn't cause an issue. Read each screen and keep clicking next. Eventually it will do its thing. It takes about ten minutes and sometimes seems to be frozen. Have patience grasshopper.

And that's it. I'm now running pure stock (not for long I'm sure), still s-off. If you are s-on, you will have to unlock your bootloader again.

Good luck!