I'm running os x 10.10.5 and can not download el capitan or high sierra

Try for El Capitan

<https://itunes.apple.com/app/os-x-el-capitan/id1147835434?mt=12>

• MacBook (Early 2015)
• MacBook (Late 2008 Aluminum, or Early 2009 or newer)
• MacBook Pro (Mid/Late 2007 or newer)
• MacBook Air (Late 2008 or newer)
• Mac mini (Early 2009 or newer)
• iMac (Mid 2007 or newer)
• Mac Pro (Early 2008 or newer)
• Xserve (Early 2009)

Sierra

<https://itunes.apple.com/us/app/macos-sierra/id1127487414?mt=12>

• MacBook (Late 2009 or newer)
• MacBook Pro (Mid 2010 or newer)
• MacBook Air (Late 2010 or newer)
• Mac mini (Mid 2010 or newer)
• iMac (Late 2009 or newer)
• Mac Pro (Mid 2010 or newer)

See these instructions: How to download macOS High Sierra - Apple Support

You cannot download El Capitan anymore, so that's normal. High Sierra should be downloadable from here: go directly to the macOS High Sierra page.

What happens when you click on that link and press the Download button?

I had the same problem. I have a 2014 Macbook Air. I had to have 10.10.5 all updated then I had to directly download high sierra from the app store. It was a pain in the butt to figure out. Spent a good 3 hours downloading things I didn't need to finally find what would work.

My machine is roughly 9-10 years old. Works fine, but it's too old to update to High Sierra. However, for a piece of software I need to RDP into work, I need a more recent version of the OS than 10.10.5. Something in between needs to be available.

Try downloading in the Safe Mode or another admin account.

Safe Mode - About

Safe Mode - Yosemite

YES !! We have been trying for a week now and we can't seem to get updates/upgrades for either! It is a major headache.