Partitioning hard disk in a Mac with Sierra

[MicheleSamaja]

I am trying to partition the hard disk to accommodate an older MacOs version that can run only when needed. I used the Disk Utility and all went smooth until pressing the Apply button. After a few minutes, when "shrinking file system", the Mac stops and restarts, of course without creating the new volume. Do you now how to handle this? Thanks!

 

[Bazza1]

Is it even possible to partition the Mac's drive these days? I mean, beyond the virtual partitions created by products like Parallels. Its been years since I even considered that sort of thing - and now, with an MBA with a factory SSD, size would preclude it.
I did partition an external drive with my MBA - half for Time Machine and half for misc storage - and that went off without issue. I don't suppose the older OS would run off an external drive?

 

[njlx2016]

It is possible to install and run Mac OS from an external drive.

If the older Mac OS installation is only going to be used occasionally, I would suggest looking into installing it on a fast external drive - ideally an SSD with at least a Thunderbolt connection if you Mac supports it.

I have briefly used this type of setup in the past and the speed differences vs an internal drive are negligible.

 

[Tech198]

Try booting to recovery and shrink disk as needed...... I do know Disk Utility has it's 'quirks' when the OS is running.. For some reason Apple change how these are interconnected...

a.k.a he same thing happens as how u are unable to verify or repiart he boot drive for permissions, but u can outside the OS... even for external drives...For reason still unknown now in Sierra Apple cooperates first aid into a single button, completely obfuscating the repiar case.