I installed Windows 10 and now my imac wont boot and i cannot restore

[NateS]

i am using windows for about 10 years…

Since you were running a computer (Mac or Windows doesn't make any difference) without using any backup method, we naturally assumed you were a novice computer user, and for that reason everyone has tried to be very gentle and diplomatic in trying to take the sting out of that fact for you.

Incidentally, the title you gave to start the thread says "…I cannot restore…" which implied that you had a backup, which you did not.

Regards, Nate

 

[josehill]

The fact that you can see "OS X Base System" means that your hard disk is probably still good. As some of the earlier posts have suggested, you probably deleted the regular Mac partition and replaced it with a Windows NTFS partition when you installed Windows. You cannot install Mac OS on an NTFS formatted partition.

To reinstall Mac OS, you will need to delete the Windows partition (if it is still there) and then create a new "HFS+" formatted partition on the hard disk.

So, before going to the trouble of bringing the system in for service, you should try running through steps 2-8 under "Partition a startup disk" at Disk Utility 12.x: Partition a disk. You can probably search the net for "partition mac hard disk" to find some articles with example screen shots of the process.

Once you've created an HFS+ partition, you should be able to install OS X on it without any trouble.

 

[TattooedMac]

i am using windows for about 10 years and i have never experienced such a problem, i mean to format one partition and the whole hard disk vanished, operating system gone too and there is nothing you can do about it, thats not normal...

What this usually means though, is User error. Its not OS X's fault that you didn't do the right procedure to install Windows 10 Preview. As far as I can tell atm, Bootcamp doesn't support W 10 yet, as there are no drivers for Bootcamp, and probably your problem.

Virtualisation is the only safe way to put the W10 Preview on your Mac.

 

[NateS]

What this usually means though, is User error. Its not OS X's fault that you didn't do the right procedure to install Windows 10 Preview. As far as I can tell atm, Bootcamp doesn't support W 10 yet, as there are no drivers for Bootcamp, and probably your problem.

Virtualisation is the only safe way to put the W10 Preview on your Mac.

Good point.

See also: How to install Windows 10 on the Mac without spending a dime

By Peter Cohen, Wednesday, Jan 21, 2015 a 3:02 pm EST
Jan 21, 2015
How to install Windows 10 on the Mac without spending a dime | iMore

Boot Camp doesn't officially support Windows 10 yet, and as such, its drivers may not play 100 percent nicely with the technical preview if you choose that route. I plan to revisit Boot Camp support for Windows 10 after Microsoft officially releases the new version, and I'll post my results. In the interim, though, I don't recommend using Boot Camp for Windows 10 Technical Preview.

Apple's Official website also makes this very clear:
Boot Camp: System requirements for Microsoft Windows operating systems
Boot Camp: System requirements for Microsoft Windows operating systems - Apple Support

Supported versions of Windows
(Authentic, single, full-installation)
Windows XP: Home Edition or Professional with Service Pack 2 or Service Pack 3 (Boot Camp 3)
Windows Vista: Home Basic, Home Premium, Business, or Ultimate, Service Pack 1 or later (Boot Camp 3)
Windows 7: Home Premium, Professional, or Ultimate (Boot Camp 4 or 5.1)
Windows 8: Windows 8 or 8.1, Windows 8 or 8.1 Pro (Boot Camp 5.1 only)



Nate

 

[Slydude]

Just as a general note for those reading the thread in the future> I can't say whether this is true for Windows 19 since I haven't tried it yet but for earlier versions the source of accidentally deleting the Mac partition has not bee Boot Camp. The accidental erasure is almost always occurring when the user is running the Windows side of the install process.