When you do a backup you get an error 0x81000019, the message is:
"A shadow copy could not be created. Please check the 'VSS' and 'SPP' application event logs for more information. Details: Insufficient storage available to create either the shadow copy storage file or other shadow copy data. "
Backup process involves the system writer that reports files in the important applications installed on the machine. In the case where a large number of language packs is installed, the metadata file reported by this writer becomes huge in size and hence does not fit the 100 MB volume. This causes backup to fail since there is not enough space for the shadowcopy creation. Please note that this symptom is not directly observable since this metadata file is created during backup and deleted at the end.
Uninstall unwanted/unused language packs by running Lpksetup command in a command window.