After you install Service Pack 1 on a Windows 7 RTM system, the following event is logged in the Event Viewer:
Event ID: 36 Event Source: VolSnap Event Type: Error Event Details: The shadow copies of volume C: were aborted because the shadow copy storage could not grow due to a user imposed limit
Event ID 36 on volsnap is being logged during the Service Pack upgrade because there was not enough disk space in the Diff Area for the Volume Shadow Service to take a snapshot. Due to the lack of disk space in the Diff area, the operating system automatically deleted the snapshot that was taken on Windows 7 RTM before the Service Pack finished installing to make room for the next snapshot that is attempted.
When installing a major servicing update such as a service pack, the operating system will attempt to create a snapshot of the current state for restore/rollback purposes. Due to the lack of disk space available in the Diff Area, the snapshot did not successfully complete and you will be unable to rollback to the RTM state.
Before installing a service pack, make sure the system has enough disk space outlined from the following TechNet article:
The following table lists the approximate disk space requirements for the system partition, which includes the English (EN) language pack by default. Note that these requirements will increase if other language packs are installed on your computer. For more information about each installation method, see Deploy SP1.
For Windows 7 with SP1:
Approximate disk space requirements
Download size for package
X86-based: 4.1 GB
X64-based: 7.4 GB
X86-based: 537 MB
X64-based: 903 MB
X86-based: 750 MB
X64-based: 1050 MB
X86-based: 44.3 MB
X64-based: 73.7 MB
For additional information regarding Event ID 36 on server operating systems, please see the following TechNet article: