InstallShield installer archive

InstallShield installer archive is what we're calling the format of the  file included in many Windows software distributions that use the InstallShield installation software. Another filename used by the format is. Rarely, filenames  (related to Windows NT for DEC Alpha) and   (MIPS) may be found.

It uses PKWARE DCL Implode compression.

Disambiguation
It is not to be confused with InstallShield CAB, InstallShield Z, or MS-DOS installation compression.

Discussion
Based on unconfirmed information, the 16-bit  program detects the user's platform, and extracts the appropriate platform-specific installer programs from (e.g.).

Identification
Files begin with bytes.

At offset 8 is the message " ".

Sample files

 * Examples of software with such a file:, ,
 * https://telparia.com/fileFormatSamples/archive/installShieldInstallerArchive/

Links

 * FILExt page about the ??_ file extension pattern (Look for "InstallShield")