Reinstalling macOS on a 2015 MacBook Pro

If you have a Time Machine backup of macOS Catalina or earlier on an external drive that has never been used with a later version of macOS, then you can reinstall the OS from that.

It doesn't help that you have to use the iPhone hotspot for this. Yes, theoretically it should work, but you know how these things go.

Otherwise, this is a fairly common problem and it usually relates to an inability of the Mac to establish a secure connection to the download server for High Sierra. There is a fix. Please see Fix#3 in this linked document: https://mrmacintosh.com/how-to-fix-the-recovery-server-could-not-be-contacted-error-high-sierra-recovery-is-still-online-but-broken/

do you have an Apple store available to you?

In the back of the store at my (suburban Boston USA) store, there is a table with a pile of cables you can borrow and an Associate acting in the role of "Camp Counselor".

The work going on at that table is upgrades, data transfers -- old equipment to new equipment, and all sorts of similar stuff for iPhones and Macs of all types. The associate is there to offer guidance (sometimes strong guidance if needed) to get you back on track to getting your equipment running again. The store has pretty good Wi-Fi, and everybody at that table is in a similar situation -- undertaking some sort of transfer or restore using equipment new and old.

The cost for this guided self service is FREE to Apple equipment owners, in warranty or out.

You’re welcome.

Re: the TM backup - Backing up after you have a problem is too late.

The point of having a back up is to be able to recover when you do have a problem. If you don’t create a backup, then you will lose data. The time to make backups is when the Mac is working well.

Good 🍀 luck, my friend.

The other traditional go-to place with free Wi-Fi used to be Starbucks. But they are in the process of changing their corporate policy, so it is not clear whether they would let you sit for half an hour doing a re-install using their Wi-Fi. Car dealers and many other service-based businesses also offer free Wi-Fi.

Have you checked you local public library?.

<< it reinstalled OS X Lion. >>

skip ahead to install (at least) 10.11 El Capitan next, because it contains a working internet connection, where older versions do not.

SSL to TLS:

In 2015, researchers discovered that Secure Socket Layer (SSL) Internet encryption was not nearly as secure as was thought, and needed to be replaced. Internet encryption quickly moved to Transport Layer Security (TLS) which was rapidly deployed across the Internet. Over time, sites tightened requirements for what was acceptable for encryption.

Apple issued Safari version 9 in 10.11 El Capitan version of MacOS, which included TLS encryption. It was later provided by Security Update into the two previous versions of MacOS. 10.10 Yosemite and 10.9 Mavericks, PROVIDED you applied all available software updates.

MacOS versions older than those can not make a lot of secure [httpS:] connections on the Internet, because by todays standards, your proffered SSL encryption is considered inadequate.

You're welcome.

I glad to read that you've got a handle on this.

Also, I agree with @ GBA regarding the upgrade to 10.11 El Capitan. After that I'd take it straight to 10.13 High Sierra. I found that to be a very stable OS, and it'll give you most of the last little bit of life the 2011 MacBook can muster.

🙂

I was free-associating about where to go for good Free Simple Wi-Fi, and my mind wandered back to the Apple Store.

I doubt my local store is unique. It may be going on more quietly at smaller stores.

Even if heavy-duty help is not immediately available at your store, the Wi-Fi is free, and the ambience is exceptional.

That sounds like a pretty cool setup. Good on that Apple Store management team! 👍🏽

You're welcome. 🙂