Answering my own question… Our support company PTFS Europe have cracked this one. Apparently this has been seen with other 18.11 sites. The problem is with the fines.pl script taking hours and hours to run. Seems the job gets the total number of days between the due date and now. Then it iterates through every day checking if it is a holiday and if it is, decrements the total number of days. The problem is that it is only checking a couple of days a second. We have lots of “old” fines- back to 2013 and the checking was taking ages. PTFS have advised there's a caching mechanism that the problematic part of the fines calculation should be using but wasn't. They have now enable memcached to start using the cache. This allows the fine calculation to cache a particularly expensive query, reducing the time to calculate a 7 year old fine from 53s to 4s. Apparently a line has been added to our koha-conf file to cause memcached to start using the cache. Fingers crossed that fines.pl will now run correctly overnight. Ray Delahunty. This email and any attachments are intended solely for the addressee and may contain confidential information. If you are not the intended recipient of this email and/or its attachments you must not take any action based upon them and you must not copy or show them to anyone. Please send the email back to us and immediately and permanently delete it and its attachments. Where this email is unrelated to the business of University of the Arts London or of any of its group companies the opinions expressed in it are the opinions of the sender and do not necessarily constitute those of University of the Arts London (or the relevant group company). Where the sender's signature indicates that the email is sent on behalf of UAL Short Courses Limited the following also applies: UAL Short Courses Limited is a company registered in England and Wales under company number 02361261. Registered Office: University of the Arts London, 272 High Holborn, London WC1V 7EY