Is it safe to downgrade to Yosemite?

[zz00ter]

I want to downgrade to Yosemite
I do not want to do a clean install - I don't want to reinstall all my apps
Is it safe to downgrade to Yosemite?

- Yosemite installer will not open inside El Capitan
I guess I need to make a USB installer if I want to downgrade

 

[Shirasaki]

You will eventually need to reinstall everything, including your apps.

 

[beebarb]

@zz00ter
As far as I am aware, you have no choice but to do a clean install if you want to downgrade.
If you don't, the Yosemite installer will detect that a newer version of OS X is already present on the target disk, and refuse to continue.

 

[MultiFinder17]

If you have a Time Machine backup, you can use that to go back. If not, then you would need to reinstall everything.

 

[Nermal]

@zz00ter
As far as I am aware, you have no choice but to do a clean install if you want to downgrade.
If you don't, the Yosemite installer will detect that a newer version of OS X is already present on the target disk, and refuse to continue.

Actually, it lets you continue... then falls over halfway through the install. I know from experience!

 

[Queen6]

SuperDuper would be your best friend in this situation, as the OP needs to ask he/she will need do a clean install and start over from scratch...

Q-6

 

[DPUser]

If you have a Time Machine backup, you can use that to go back.

This.

 

[howiest]

If you do a full clone of your system (with SuperDuper or CCC) before diving into a brand new OS X release, you'll always have an out. Actually it's just good to have an up to date clone in any event.
I take it one step further and have 2 clones, where one is kept off-site. I refuse to get burned again.
Fool me once...

PREACHING MODE: OFF

 

[IHelpId10t5]

I want to downgrade to Yosemite
I do not want to do a clean install - I don't want to reinstall all my apps
Is it safe to downgrade to Yosemite?

- Yosemite installer will not open inside El Capitan
I guess I need to make a USB installer if I want to downgrade

You didn't say why you want to go back? It's almost certainly going to be easier to solve your problem within El Capitan than to go back to Yosemite. As other have said, unless you have cloned your boot drive before install, then you are likely out of luck.

 

[thekayman]

If you have a Time Machine backup, you can use that to go back.

Unless that backup was laready messed with by El Capitan. Can you access a TM backup made by El Capitan in Yosemite? I know I had this problem last year with Yosemite and downgrading to Mavericks.

But like other have said, why do the downgrade? El Capitan is so much better than Yosemite in every respect.

 

[Nermal]

El Capitan is so much better than Yosemite in every respect.

Apart from when it's not compatible with the third-party software and hardware that you depend on...

(Yes, I have filed bug reports).

 

[thekayman]

Apart from when it's not compatible with the third-party software and hardware that you depend on...

(Yes, I have filed bug reports).

In-compatibility is not a bug. I hope you filed those reports with the sw/hw vendors, not Apple.

 

[Nermal]

In-compatibility is not a bug.

It is a bug in this case, and even if it wasn't it would still be a valid reason to revert to 10.10.

I hope you filed those reports with the sw/hw vendors, not Apple.

The hardware in question is two different USB microphones from different vendors. Both of them now fail under 10.11 using the Apple-supplied driver, so I have indeed reported the issue to Apple - and Apple has confirmed the bug.

The software issue, on the other hand, is indeed with the software vendor.