I have installed windows 10 64 bit via bootcamp but I have problems with the bootcamp support 5.1.5769 drivers. I get the error 43 code. Is there a workaround?
Encountering problems using Boot Camp Support Software 5.1.5769 should be expected since this version is not for your Mac. Apple explicitly states this is for an iMac (Retina 5K, 27-inch, Late 2014) and a Mac Mini (Late 2014).
From Apple's point of view, this would be the answer for installing Windows 10 on your Mac.
Use the Boot Camp Assistant to install Windows 8.1. Your Mac does not support Windows 10.
Of course there is nothing stopping you from using a Windows 10 ISO to upgrade to Windows 10. However, the current release of Windows 10 may not work with your Mac. You may need to try an older release. You can use Rufus to download an older release of Windows 10. Rufus requires Windows, so you will need a machine that has Windows already installed. You should also be able to run Rufus in a Windows virtual machine on your Mac.
I have posted an answer which provides a method of obtaining the links to all Windows Support Software downloads Apple has documented is for a given Mac. Below is the output from executing the script using your Mac's model identifier.
Marlin: davidanderson$ ./GetPkgUrl --clean --legacy --quiet MacBookPro8,3 Matching URL's are listed below. http://swcdn.apple.com/content/downloads/04/44/041-84708/yq9w47gthzu8e8fqmad6hx0vs15fuk4540/BootCampESD.pkg http://swcdn.apple.com/content/downloads/45/20/041-85204-A_24VIQ2D28M/3ln1dqstqacwzknssu2fyu3rqhf3y3b94n/BootCampESD.pkg http://swcdn.apple.com/content/downloads/26/08/041-84821-A_AMCFPC3QDK/4fffs8qgdflw7pn1finqqd40gifh41mvs6/BootCampESD.pkg http://swcdn.apple.com/content/downloads/57/55/041-84868-A_402D0DFI39/6uz8hhgtd4b87t00mrq0uihiop5ivumsbk/BootCampESD.pkg Marlin: davidanderson$ ./GetPkgUrl --clean --quiet MacBookPro8,3 Matching URL's are listed below. http://swcdn.apple.com/content/downloads/04/44/041-84708/yq9w47gthzu8e8fqmad6hx0vs15fuk4540/BootCampESD.pkg http://swcdn.apple.com/content/downloads/26/08/041-84821-A_AMCFPC3QDK/4fffs8qgdflw7pn1finqqd40gifh41mvs6/BootCampESD.pkg http://swcdn.apple.com/content/downloads/57/55/041-84868-A_402D0DFI39/6uz8hhgtd4b87t00mrq0uihiop5ivumsbk/BootCampESD.pkg Marlin: davidanderson$
For convenience, below I have provide links to the downloads.
One of the downloads should produce the same files as a Boot Camp Support Software 5.1.5621 download. I would also assume a download of the Windows Support Software by using the Boot Camp Assistant should produce the same files as one of the downloads.
I can not provide a way to determine which download is the most current; other than simple inspection. There is also Tim Sutton's brigadier software which somehow knows which download to provide for your use. I have never used brigadier, but I though I should mention its existence.
You could adapt this answer to install Windows 10. Some differences are noted below.
You can omit the following files and folders from the USB flash drive.
Folders Files From Windows 7
From Microsoft Edge
From Microsoft Update Catalog
You should substitute the
d:\sources\install.esdfile for the
d:\install.wimfile when entering the commands.
Do not install any of the hotfixes.
Do not install Microsoft Edge.
Note, I have not tested to see if there are other differences.