How to fix Unibeast's "Selected Mac OS X Installer is Incomplete" error

Selected Mac OS X Installer is Incomplete

Your selected Mac OS X Installer is incomplete. Please delete all copies of the installer from all mounted volumes and redownload it again from the Mac App Store.

Do you receive above error message when you try to prepare a bootable USB  using Unibeast and a OS X installer downloaded from another machine, or a torrent? and you are 100% sure the downloaded installer is genuine copy?

Actually you can resolve this by doing either,

1. Simply changing the system time or

2. Patching Unibeast to remove a validation. 

(Changing 0000000100003262         je         0x1000032a2 to a NOP in Unibeast 6.1.1)

Both can be done easily. But I'm going to describe only the first option here. 

First let me explain few validations which are done by Unibeast before it allows you to create the bootable USB.

1. First validation it does is the Installer name and the path. Installer should be available at the /Applications directory with the correct name.

E.g.: 

/Applications/Install OS X Yosemite.app

/Applications/Install OS X El Capitan.app

2. Second validation is that,

If the installer is for Yosemite, then it checks for the string "com.apple.InstallAssistant.Yosemite" in the /Applications/Install OS X Yosemite.app/Contents/_MASReceipt/receipt file using "grep -q" command.

If the installer is for El Capitan, then it checks for "

com.apple.InstallAssistant.ElCapitan" in the /Applications/Install OS X El Capitan.app/Contents/_MASReceipt/receipt file using "grep -q" command.

3. The third validation is that it validates the signature of the receipt. This is the moment you get the "Installer is Incomplete" error message. This can happen either your receipt file is actually changed by someone or the certificates included in the receipt file are expired.

You can view the certificate information executing below command, (first change directory to /Applications/Install OS X xxx.app/Contents/_MASReceipt/ directory)

openssl pkcs7 -inform der -in receipt -print_certs -text

If your machine time is not within the validity period of the certificates, the signature validation is failed and Unibeast prompts the "Installer is Incomplete" error message.

e.g.:

openssl pkcs7 -inform der -in receipt -print_certs -text | egrep 'Not Before|Not After'

            Not Before: Nov 11 21:58:01 2010 GMT

            Not After : Nov 11 21:58:01 2015 GMT

            Not Before: Feb 14 18:56:35 2008 GMT

            Not After : Feb 14 18:56:35 2016 GMT

            Not Before: Apr 25 21:40:36 2006 GMT

            Not After : Feb  9 21:40:36 2035 GMT

In this case, the lowest "Not After time" is Nov 11 21:58:01 2015 GMT and the highest "Not Before time" is Nov 11 21:58:01 2010 GMT. Therefore the time of your machines should be within Nov 11 21:58:01 2010 GMT and Nov 11 21:58:01 2015 GMT.

Therefore if you change the machine time appropriately, let's say 2015/01/01 then Unibeast will proceed without prompting the  "Installer is Incomplete" error message. :)

Note: I think above validation was introduced by Unibeast developers to address a legal issue rather than making sure you have a genuine copy, because you can still have a modified installer files even when the receipt validation is passed.  So if you download the MAC OS X Installer from a torrent site or any other place, check the MD5 or SHA1 of the InstallESD.dmg file.

For Further reads about apple receipts,

https://developer.apple.com/library/mac/releasenotes/General/ValidateAppStoreReceipt/Chapters/ValidateLocally.html

https://magervalp.github.io/2013/03/19/poking-around-in-masreceipts.html