Metadata and appstream Error while Updating

Question

I am getting an error while updating as a root. After Update log below error was shown in terminal.

AppStream system cache was updated, but problems were found: Metadata files have errors: /var/cache/app-info/xmls/fwupd.xml
Reading package lists... Done
E: Problem executing scripts APT::Update::Post-Invoke-Success 'if /usr/bin/test -w /var/cache/app-info -a -e /usr/bin/appstreamcli; then appstreamcli refresh-cache > /dev/null; fi'
E: Sub-process returned an error code

I followed this answer and executed sudo apt install appstream/xenial-backports.

My appstream package is already updated:-

$ appstreamcli --version
AppStream CLI tool version: 0.10.6

After, force refreshing the cache data. I am getting the following error:-

$ sudo appstreamcli refresh --force
AppStream system cache was updated, but problems were found: Metadata files have errors: /var/cache/app-info/xmls/fwupd.xml

Answer 1

There seemed to be an xml error in line 265 of file /var/cache/app-info/xmls/fwupd.xml mentioned in the metadata error output.

Change Firmware_SF30&SN30 to Firmware_SF30&SN30