Some of the user suddenly get this type of display. please assist
Coding error detected, it must be fixed by a programmer: Failed to unserialise data from file. Either failed to read, or failed to write.
by Mogana Logan -
Number of replies: 3
In reply to Mogana Logan
Re: Coding error detected, it must be fixed by a programmer: Failed to unserialise data from file. Either failed to read, or failed to write.
by Leon Stringer -
Which version of Moodle is this?
Enable debugging – under Site administrator ▸ Development ▸ Debugging, set Debug messages: DEVELOPER and Display debug messages: Yes – to show more details of the error:
Then share the detailed error with us and we'll try to help.
In reply to Leon Stringer
Re: Coding error detected, it must be fixed by a programmer: Failed to unserialise data from file. Either failed to read, or failed to write.
by Megan Thoresson -
Thank you - I will try this. I rang the people who host our server after this, and found that our Moodle has been unsupported for several months. They are just about to upgrade , and perhaps this will also fix it? If not, once the upgrade is complete, I will try your suggestion and get back in touch. Thanks for your help. 
In reply to Mogana Logan
Re: Coding error detected, it must be fixed by a programmer: Failed to unserialise data from file. Either failed to read, or failed to write.
by Emma Richardson -
I would initially suspect a permissions issue - check your moodledata folder has the correct permissions.