[Evolution] Empty cache file

[Mark <mark genusone co uk>]

Hello list,

My Evolution on this laptop seems to be rather broken as of this
morning. For any new messages synchronised from an IMAP folder, I get
an error when opening them along the lines of:

Empty cache file:
/home/mark/.cache/evolution/mail/a6bb2aca8488f40e1eebd248af7c9e2a82c86f
05/folders/INBOX/cur/02/6469

Looking at the referenced files, they certainly have zero size. I've
Googled for the problem but none of the solutions or causes seem to be
correct. Looking at Syslog, I also see multiple errors for Evolution:

Jan  5 11:00:44 mark-Latitude-E5270 evolution[4054]: Cannot register
URI scheme gtk-stock more than once
Jan  5 11:00:44 mark-Latitude-E5270 evolution[4054]: Cannot register
URI scheme evo-http more than once
Jan  5 11:00:44 mark-Latitude-E5270 evolution[4054]: Cannot register
URI scheme evo-https more than once
Jan  5 11:00:44 mark-Latitude-E5270 evolution[4054]: Cannot register
URI scheme mail more than once
Jan  5 11:00:44 mark-Latitude-E5270 evolution[4054]: Cannot register
URI scheme cid more than once
Jan  5 11:00:58 mark-Latitude-E5270 evolution[4054]: Cannot register
URI scheme evo-file more than once
Jan  5 11:00:58 mark-Latitude-E5270 evolution[4054]: Cannot register
URI scheme gtk-stock more than once
Jan  5 11:00:58 mark-Latitude-E5270 evolution[4054]: Cannot register
URI scheme evo-http more than once
Jan  5 11:00:58 mark-Latitude-E5270 evolution[4054]: Cannot register
URI scheme evo-https more than once
Jan  5 11:00:58 mark-Latitude-E5270 evolution[4054]: Cannot register
URI scheme mail more than once
Jan  5 11:00:58 mark-Latitude-E5270 evolution[4054]: Cannot register
URI scheme cid more than once

The application version is 3.36.5.0 running on Ubuntu 20.04. I've got 3
separate IMAP accounts, one of which is GMail and I've had quite a few
problems with the GMail account over IMAP but I thought I'd solved
these by reducing the size of GMail folders and not synchronising all
of them. This problem, however, affects all of the accounts so I don't
think it's a GMail problem.

I'm not sure if the Syslog errors for Evolution are related to the
Cache error but it's certainly a coincidence that both are concurrently
present.

-- 
Mark.
----
Genus One Ltd
Information Security Solutions
www.genusone.co.uk

Genus One Ltd is a company registered in England with registration
number 8436731.
Registered Office: Union House, 111 New Union Street, Coventry, CV1
2NT