Restart the computer then immediately hold the Command key and the letter R key together until you see the Apple Logo. This will boot to the Recovery HD partition. When it boots you will see a window called Utilities, select the Disk Utility and then select Continue. Then in Disk Utility select Macintosh HD in the left column and then select Verify Disk on the right. If that is OK in green type then select Repair Permissions. If it is not ok let me know.
If that is ok then Restart open the App Store and try installing Yosemite again
Yes installed again and Came back to computer to find Users and groups screen displayed and after installation finished up with 'try again'
Are you using FileVault?
I have checked fire vault is off
So Verify Disk was OK in green type and then you Repaired Permissions? If so restart then go to Applications and drag Install OS X Yosemite.app to the trash, then go to App Store and redownload
Empty the trash too
So Verify Disk was OK in green type and then you Repaired Permissions? If so restart then go to Applications and drag Install OS X Yosemite.app to the trash, empty the trash, then go to App Store and redownload
Have reloaded and ended with the same error message --- try again!
Maybe continue to morrow with some other process under your guidance
I have sent an e mail to my server "postofficebroadband.co.uk" to ascertain how I can tell when my monthly ration of downloads ,which is 10 GB, has been reached. I will contact you again after I have received a reply from them.
PS I wonder if it would make any difference if I turned off my printer before attempting yet another 2 hour download
I hope to make contact again on next tuesday around 10.30
I still await a reply from my server to ascertain how and when they cut off my download ration. Meanwhile my 10 year old printer is out of commission and i am hoping to ,next week. to replace it with a "Brother" DCP J552DW A4 A-1-0 inkjet printer.
The urgency to upgrade to Yosemite has receded time being. Thanks help so far. I may need more help if setting up the new printer proves troublesome
Have now received confirmation from my server that I have not exceeded my download ration, so that is not the reason .
My downloads folder shows I have 4 incompatible downloads.
Might these cause the pausing? They are Pages, iPhoto, Keynote & Numbers.
Should I delete them via Clean My Mac before I try once more to download Yosemite?
I now have a new Brother printer installed and have repaired permissions.
Any suggestions what to do next? There is no urgency!
Before downloading I have
Disconnected my new Brother printer
Checked fire vault & fire wall is off
Checked energy saver is set at never
Verified & repaired permissions
Quit running apps
Still finish with "An error occurred while preparing the installation. Try running the installation again"
I still finish up with"Failed to download use the purchases page & try again"
Consequently my patience is exhausted and so have decided to transport my iMac to Tec in Bradford who supplied it and who are Apple authorised solution experts. This will be deferred until the new year. Meanwhile thank you assistance and best wishes happy Christmas and New Year.