Waterfox Update

[#1]

I've used Waterfox for some time now with no problems.

However this morning I updated to version 55.2.0 from version 54.0.1.

When I try to run the application I get

XML Parsing Error: undefined entity
Location: chrome://browser/content/browser.xul
Line Number 365, Column 5: <key id="key_quitApplication" key="&quitApplicationCmd.key;"
----^

I have found one other person with the same issue so far and I'm currently running Chrome temporarily.

[#2]

I have uninstalled Waterfox and installed the latest incarnation of Firefox and it has (unsurprisingly) picked up where Waterfox left off.

So I am back up and running with a familiar browser.