I've been trying to install Windows 7 on my MacBook Air, and keep running into hardware support/recognition problems. These problems have been reported elsewhere, but no solutions are known to me, and the work-arounds do not work. The scenario... MacBook Air 13 inch, early 2014 Mac OS 10.9.4 on a single partition taking up the whole SSD Windows 7 Professional, 64 bit <- is what I'm trying to install First of all, this is what Apple officially claims/says/recommends: - That my MBA is compatible, can install Win 7, and should use Bootcamp 5: https://support.apple.com/en-us/HT205016 - First problem: the download link does not work at https://support.apple.com/kb/DL1721?locale=en_US STRIKE ONE. I then had to manually find the downloads, which are at https://support.apple.com/downloads/boot-camp And after wasting time checking which one is appropriate, concluded it should be 5.1.5640: https://support.apple.com/kb/DL1721?locale=en_US So here's what happens, when following Apple's instructions: Put Win 7 DVD into USB optical drive. Boot Camp ASSistant (emphasis added) could not build boot image from optical. Had to use DiskUtility to dump the DVD into an ISO, more time wasted. Run Boot Camp Assistant. I check all 3 boxes: create bootable USB, download latest drivers, and install Windows. BTW, this is a major peeve already: I had to get an external optical drive AND a USB flash drive. $$$!!! Boot Camp Assistant took forever to download... 900+ MB worth of device drivers! I mean, these are device DRIVERS, do they need to be this huge?!?! Bootable USB drive created successfully. It booted fine, ran all the installation steps for Windows 7, finished installing all files, then came the time to actually boot the newly installed Windows from the MBA. Then I get a boot failure: Windows cannot verify the digital signature of driver "applessd.sys". I'm not the only one who has hit this: https://stackoverflow.com/questions...ssd-sys-digital-signature-can-not-be-verified And it just happened that the above link was the first solution returned by web search, so out of desperation I tried its "solution" even though I did notice these drivers were for an older revision of the MBA. It did not work: upon doing a full reinstall of Windows, I ended up at a setup screen with non-responsive keyboard and trackpad. 2 hours wasted. Then I remembered that the Boot Camp 5.1.5640 came with another set of drivers. So I used them to overwrite the ones that Boot Camp Assistant put into my USB drive. Reinstall Windows, ended with non-functional keyboard and trackpad, 2 more hours wasted. Then I stumbled upon this next solution: https://discussions.apple.com/thread/7171609?tstart=0 Deleting "AppleSSD.sys" actually worked. However to do that, it was another side excursion of re-attaching optical drive, booting from DVD, going into advanced tools, launching a command prompt, hunting down the applessd.sys file (of which there are 2 copies), deleting both, then rebooting. Surprise, Windows 7 actually booted to its GUI successfully! Come to think of it, applessd.sys was only a few tens of KB; you cannot implement a real SSD driver in that tiny size. The fact that Windows could finish booting using some other (probably stock) driver indicates this "applessd.sys" is not really important. So this begs the question, if this file is non-essential, why is it being included in the critical path of booting Windows? And more importantly, why and how could Apple let its digital signature become invalid... or perhaps expired? IMO, no matter what licensing problems or corporate politics might exist between Apple and Microsoft, this type of problem SHOULD NEVER BE EXPOSED TO THE END USER. Unfortunately that's not where the story ends. Even though at this point Windows 7 did successfully: - boot from USB into its installation environment - load all drivers from the $WinPE$ environment, permitting the execution of the installation process - boot from its installation on the MBA's SSD ...It turns out that other necessary support drivers are not being installed, namely those for the SPI keyboard and trackpad, and the built-in USB hub. I am left with a Windows GUI to do the finishing touches (such as setting language, region and password), but I can't do anything because NEITHER THE KEYBOARD NOR THE TRACKPAD ARE RESPONSIVE!!! Even if I plug in standard USB keyboard and mouse, they do not work because (I suspect) no driver for the built-in USB hub has been loaded. Even though I know there is a "setup.exe" and a bunch of installable drivers on the bootable USB drive, I have no way to launch the installation for them in order to install the necessary drivers, WHICH IS THE POINT OF RUNNING BOOTCAMP IN THE VERY FIRST PLACE. So I ended up with a Windows 7 installation that seemed to have completed, but is COMPLETELY UNUSABLE. Way to go Apple, you managed to make the installation process every bit as obfuscated, convoluted, frustrating and UNSUCCESSFUL as IBM's OS/2 back in the 1990s.