If you've downloaded bootcamp drivers for Macs to run Windows 7 or 8, but have done the download in Windows, you may be stuck on how to open the downloaded BootCampESD.pkg file you've now got.
The answer is to get a copy of 7-zip, which is free, and which is your 'Swiss army knife' to open the Apple .pkg and .dmg files and the ISO file inside.
- Launch 7-zip
- In 7-zip, open the BootCampESD.pkg. Inside you'll find a Payload file and a few other files. Double click the Payload file.
- Inside is a folder, which you double click. Inside that another folder, which you double click. Inside that ... just keep clicking down the levels of nested folders.
- Eventually, several levels down, you'll get to a file called 0.Apple_ISO or some such.
- Now, extract this o.Apple_ISO to the desktop (or somewhere) and rename it to Apple.ISO.
- Now, either: Mount it by double clicking it—should work in Windows 7—or else by getting hold of PowerISO or similar; OR use 7-zip again to open this ISO file, and extract the contents to a folder.
- These are you driver installers. Create an empty folder on your desktop, and drag them out into it.
- Finally, open the folder you just created, and run the setup.exe