running Catalina and High Sierra on same Mac

[odamizu]

I wanted to start a thread for Mac users who are thinking about upgrading to macOS 10.15 Catalina (once it's released), but still want/need to be able to run 32-bit apps or other software that may balk on Catalina.

A discussion in the Calibre forum on Kindle for Mac raises this issue, followed by this suggestion:

Originally Posted by tomsem

... Apple allows previous versions of macOS to be virtualized, for precisely the reason that some apps may not be compatible with the latest version.

So why not set up a VM with a working de-DRM environment so you don’t have to adapt to changes that the world throws at us? Also makes it much easier to set up on a new computer.

I've also been contemplating this Apple support article on Installing macOS on a separate APFS volume.

Any thoughts and suggestions on different ways to run Catalina and High Sierra (or older macOS) on the same Mac, pros and cons, greatly appreciated.

[pwalker8]

Hum, if I recall correctly wasn't High Sierra the version of MacOS that broke most of the de-DRM tools that worked using iTunes? I'm pretty sure that most of the de-DRM tools say that they work with 10.12 and below.

[odamizu]

Originally Posted by pwalker8

Hum, if I recall correctly wasn't High Sierra the version of MacOS that broke most of the de-DRM tools that worked using iTunes? I'm pretty sure that most of the de-DRM tools say that they work with 10.12 and below.

The Calibre thread was addressing Kindle for Mac 1.23.1 and Alf's DeDRM tools, both of which run fine on High Sierra. However, Kindle for Mac will likely become problematic on Catalina since K4Mac 1.23.1 is 32-bit and there are issues getting the 64-bit version (1.25+) to work with Alf.

However, that's just one reason why someone might want to run two versions of macOS on a single Mac, and I was hoping to start a discussion on options, pros and cons.

[pwalker8]

Originally Posted by odamizu

The Calibre thread was addressing Kindle for Mac 1.23.1 and Alf's DeDRM tools, both of which run fine on High Sierra. However, Kindle for Mac will likely become problematic on Catalina since K4Mac 1.23.1 is 32-bit and there are issues getting the 64-bit version (1.25+) to work with Alf.

However, that's just one reason why someone might want to run two versions of macOS on a single Mac, and I was hoping to start a discussion on options, pros and cons.

Well, certainly you can do it, but you would need a pretty beefy machine to avoid resource issues. Dual booting has been around on the mac for quite a few years. Most people used it to boot between the mac and windows simulators. I did it when I first switched to macs. As I remember, the biggest issue was setting up the partitions correctly.

Apparently, you can also make an external disk, such as a external hard disk or even a thumbnail, bootable and dual boot that way. That might be a better choice for what you are talking about. That way you don't have to worry about partitioning. Hum, I might try that, though I think that I would want to use a larger external drive for my purposes. Still it might be an interesting experiment.

[OtinG]

After I purchased my MBP 15" Retina a fews years back, I re-purposed my older Mac Mini 2012. I used Bootcamp to partition the 500 GB HDD and Installed High Sierra on one partition and Windows 10 on the other. It works pretty well, despite the age of the Mac Mini 2012 and the fact that it runs a 2.6 GHz Intel Core i5, but it does have 16 GB of RAM. Win 10 actually runs a little faster than High Sierra on it, if you overlook the fact that every few days Win 10 wants to install new updates which usually take quite a while to complete.

I would not have used Bootcamp on my primary computer. The Mac Mini was old and was destined as a backup in case something happened to my MBP, beyond that it would have done little more. So it seemed a no-brainer to use it with Bootcamp to create a dual boot system with Win 10. I have a lot of apps that I use to program ham radios and scanners that do not run natively on Mac, and ditto for some of my astrophotography related apps. I do have an old Lenovo Yoga 2 11" laptop, but it is maxed out at 4 GB of RAM and has a low powered processor. Win 10 on the Mac Mini runs much better than it does on the old laptop.

I guess you could run another version of Mac OS X in the second partition rather than install Win 10. I don't think I would want to do that though, especially on my primary computer. If de-DRM stuff works on Win 10, that might be the better option. I used to do the de-DRM stuff years ago, but I quit a long time ago and have not kept up with it. I never did use calibre much, so ditto. So I'm not sure how, or if, it would work on Win 10.

ETA: My Amcrest surveillance cameras still use a 32-bit app. The app is becoming quite unstable on my MBP running Mojave, but it still works very well on my Mac Mini running High Sierra. Every Mojave update seems to cause more issues with that app suite. And just recently within the past few weeks some parts no longer work at all in Mojave but work fine in High Sierra. I have not updated Mojave in quite a while, whenever the last update was released as it is up to date. Apple did push some secret squirrel updates out though. The Amcrest software has not been updated in a couple of years. Yet it is getting more and more unstable on Mojave but works fine on High Sierra. The Amcrest app and web browser sites are becoming unstable on iOS 12.3 and no longer work well via Safari.

[pwalker8]

In general, abandonware tends to work best on the version of the operating system it was last updated for and gets more iffy with each new OS release. That's to be expected since they update the API on a regular basis.

[OtinG]

Originally Posted by pwalker8

In general, abandonware tends to work best on the version of the operating system it was last updated for and gets more iffy with each new OS release. That's to be expected since they update the API on a regular basis.

In the case of Amcrest it is really not abandonware since they are still developing new surveillance cameras and updating the FW to existing ones. They have merely become lax at updating the software for managing the devices. But my point was not about any particular "abandonware," it was about the fact that more issues in running 32-bit apps are creeping into Mojave, and Catalina will likely be far more aggressive against using these older apps. So far High Sierra is much better for running abandonware.

[odamizu]

Originally Posted by pwalker8

... Apparently, you can also make an external disk, such as a external hard disk or even a thumbnail, bootable and dual boot that way. That might be a better choice for what you are talking about. That way you don't have to worry about partitioning. Hum, I might try that, though I think that I would want to use a larger external drive for my purposes. Still it might be an interesting experiment.

That is a very interesting idea. Thanks! If you try it, I would be interested in hearing how it goes.

Originally Posted by OtinG

... more issues in running 32-bit apps are creeping into Mojave, and Catalina will likely be far more aggressive against using these older apps ...

My understanding (which could be wrong) is that when it comes to Catalina running 32-bit apps, it's a flat no, will not run, no maybes about it. Have you read otherwise?

[pwalker8]

Originally Posted by odamizu

That is a very interesting idea. Thanks! If you try it, I would be interested in hearing how it goes.



My understanding (which could be wrong) is that when it comes to Catalina running 32-bit apps, it's a flat no, will not run, no maybes about it. Have you read otherwise?

I've already ordered an external hard drive and should get it tomorrow sometime. I'll let you know how it goes. I'll likely put Sierra on the external drive and have the current release on the primary drive. I have Catalina on a laptop. I had some issues with the second beta and was sending bug reports regularly, but the most recent beta is doing pretty well.

[pwalker8]

Originally Posted by OtinG

In the case of Amcrest it is really not abandonware since they are still developing new surveillance cameras and updating the FW to existing ones. They have merely become lax at updating the software for managing the devices. But my point was not about any particular "abandonware," it was about the fact that more issues in running 32-bit apps are creeping into Mojave, and Catalina will likely be far more aggressive against using these older apps. So far High Sierra is much better for running abandonware.

I suspect it has a lot less to do with 32 bit and a lot more to do with changes to the various API's that are being called. Check your system log. I suspect you will see all sorts of errors being generated.

[odamizu]

Originally Posted by pwalker8

I've already ordered an external hard drive and should get it tomorrow sometime. I'll let you know how it goes. I'll likely put Sierra on the external drive and have the current release on the primary drive. I have Catalina on a laptop. I had some issues with the second beta and was sending bug reports regularly, but the most recent beta is doing pretty well.

Wow, you're fast! I'm really intrigued. Thanks!

[pwalker8]

It works. The trick is you need to install High Sierra on the external drive before you upgrade since you can't run the High Sierra installer from a newer version of the operating system. I did have to jump through a lot of hoops before I figured it out. I actually ended up installing it on a thumb drive that I had. For some reason, the external hard drive was being a bit balky.

This doesn't really help me a lot. Running Sierra off of a USB drive is pretty darn slow. Running on the mac mini works just as well for me. Now that I have the alternative working, I might try upgrading my mac mini to Sierra.

[odamizu]

Originally Posted by pwalker8

It works. The trick is you need to install High Sierra on the external drive before you upgrade since you can't run the High Sierra installer from a newer version of the operating system.

Thanks! My reason for trying this would be to be able to test an OS before installing it on my primary Mac (which is currently running High Sierra).

Would this be feasible?

• Install High Sierra on external drive
• Boot from external drive, then upgrade to either Mojave or Catalina beta or Catalina official release when it comes out. Would Mojave/Catalina on the external drive receive updates through the App Store same as any other Mac? If not, how would I update it?
• If the new OS works for me, erase/reformat external drive and re-install High Sierra on external drive
• Upgrade primary Mac to Mojave/Catalina, leaving me with a bootable High Sierra drive to run software that balks on Mojave/Catalina

If it sounds like this may work, I may give it a try.

... I actually ended up installing it on a thumb drive that I had. For some reason, the external hard drive was being a bit balky.

What kind of balkiness? I am considering an external SSD drive. Maybe the Samsung SSD T5.

Also, just to make sure I understand, if I boot from an external drive, it's like having a different and separate computer from my primary Mac? I would create new user accounts and re-install apps, just as if it were a new computer?

[cedhax]

Originally Posted by odamizu

...
Also, just to make sure I understand, if I boot from an external drive, it's like having a different and separate computer from my primary Mac? I would create new user accounts and re-install apps, just as if it were a new computer?

See https://support.apple.com/en-us/HT202796

Suppose you install two versions of macOS A and B on two drives/partitions respectively.

You can use the same user account, but you don't have to re-install any app that is compatible with both A and B. Otherwise, re-install some apps on an as-needed basis.

If you Mac has USB 3 or some even faster interface, booting from an external SSD should be fast enough. These days SSDs are pretty inexpensive. I tend to keep one for some older version of macOS for some selective apps (similar to your intended use case), and another one for future beta OS for playing around, while keeping the internal SSD as my day-to-day workhorse.

[odamizu]

Originally Posted by cedhax

... Suppose you install two versions of macOS A and B on two drives/partitions respectively.

You can use the same user account, but you don't have to re-install any app that is compatible with both A and B. Otherwise, re-install some apps on an as-needed basis ...

In that case, my original understanding was incorrect.

Looking at my Mac's directory, I have:

• Applications
• Library
• System
• Users

1) If I have High Sierra installed on my Mac and I install Mojave on an external drive, what exactly would be installed on the external drive? Just the System folder? Then the external drive would share the Applications, Library, and Users folders with my Mac? Wouldn't there be a risk of adverse effects and incompatibilities between the two systems?

2) If Apple releases a software update for Mojave, which is on the external drive, how would that work? Would I be alerted the next time I booted from the Mojave drive and the update would be applied to Mojave without affecting the High Sierra system on my Mac?

I am risk-averse and don't want to do anything that might mess up my primary Mac.

Thank you