System.IO.InvalidDataException / GZip Error When Upgrading Sitecore

Follow

Description

When upgrading a Sitecore instance where Active Commerce is already installed, you may receive this error when attempting to update:

System.IO.InvalidDataException: The magic number in GZip header is not correct. Make sure you are passing in a GZip stream.

This has been witnessed when updating from Sitecore 7.1 to 7.1 Update 2.

Cause

Cassette, a minification and bundling tool, appears to be interfering with the update.

Solution

Add the following configuration to your web.config file:

<configuration>
<configSections>
....
<section name="cassette" type="Cassette.CassetteConfigurationSection, Cassette" />
</configSections>
<cassette rewriteHtml="false" />

Remove this configuration after the Sitecore upgrade is complete.

Have more questions? Submit a request

Comments