A 0-byte file might be returned when compression is enabled on a server that is running IIS

This article helps you resolve the problem where a 0-byte file might be returned instead of the expected file when compression is enabled on a server that is running Microsoft Internet Information Services (IIS).

Original product version:   Internet Information Services 8.0, 8.5
Original KB number:   817442


When compression is enabled on a server running IIS, and an HyperText Transfer Protocol (HTTP) request is served from the IIS compression directory, a 0-byte file may be returned instead of the expected file.


You may only see these symptoms if HTTP Static Compression is enabled.


Antivirus software running on the IIS server is scanning the IIS compression directory.


Exclude the IIS compression directory from the antivirus software's scan list. The steps may vary based on the antivirus software you're using. Microsoft recommends you contact the manufacturer of the antivirus software for information about how to exclude directories from scanning.

More information

The default compression directory in IIS 6.0 is %systemroot%\IIS Temporary Compressed Files. This directory may have been changed to another location. In IIS 7.0 or a later version for IIS 7.0, the default location of the compressed file cache is %SystemDrive%\inetpub\temp\IIS Temporary Compressed Files.

To verify the compression directory, follow these steps:

  1. Select Start, point to Programs, point to Administrative Tools, and then select Internet Information Services (IIS) Manager.
  2. In IIS Manager, right-click the Web Sites folder, and then select Properties.
  3. Select the Service tab.
  4. Under HTTP Compression, make sure that Compress static files is selected, and then locate the path to the temporary directory.