Update on the recent problems users have experienced and how we’re fixing them – July 2018 

Message from Laura Thomson, Head of Reference Management

We know it’s been a difficult time for a number of users who experienced problems as a result of finding some of their PDFs missing from Mendeley. Many of the team here at Mendeley have been researchers ourselves, so we understand the concern losing PDFs and annotations must have caused. We apologize unreservedly. Below you will find an update of what happened and the steps we’ve taken to restore users’ files.

What happened?

Two incidents happened around the same time that affected users’ files and annotations, which meant that some users could not see or access their files and annotations. Firstly, some files that were added to Mendeley before 2012 were accidentally moved from our live storage system to our archive system.  Secondly, a separate bug caused files and annotations to be flagged as deleted in certain circumstances.

What’s the solution?

Our developers have been working full time on fixing these issues since we identified them, with the aim of being able to restore all users’ data as quickly as possible. It has taken us longer than we would have liked to address all the issues, for which we apologize. The following is a summary of the steps we have taken:

For the archiving problem:

• We’ve identified and stopped the root cause of the problem, so that older files are no longer moved from live storage to archive storage when they shouldn’t be.
• For users affected by this problem, we’ve restored all but about 3,500 files, and users should see these the next time they sync. Active users who had one or more unrecoverable files in their library will be contacted individually by us via email.

For the bug:

• We’ve recovered the files and annotations from our backup systems, and restored them to users’ accounts, along with the relations between them. In most cases, your files and annotations will be restored after a sync. If you are using Mendeley Desktop on more than one machine, then additional steps may be required. Please see this blog post for further instructions.
• We have fixed the root cause issue causing files and annotations to be deleted, and the fix was included in our 1.19.1 release of Mendeley Desktop.

In both cases, we’ve worked with individual researchers who took the time to give us detailed information on the problems they experienced, and tested solutions for us. We are very grateful to those individuals, and all the other researchers who provided us with feedback and insights to help address these issues.

What are we doing to avoid the situation happening again?

We have put in place several measures to make sure that errors of this kind are prevented from happening in future. These include stricter controls around archiving of data, and additional monitoring and alerting across our products and systems to detect problems earlier.

One thing we’ve learned is that recovery from this situation took us too long. Partly this is to do with having very large volumes of user data to deal with. We are sorry that many of you had to wait a very long time to know what had happened to your files, and for the stress that may have caused. While we’re pleased that we’ve been able to restore most files, we are reviewing back-up procedures with the goal of enabling us to recover data much more quickly than we were able to do this time.

What to do if you are still having problems with missing PDFs:

If you are still experiencing issues that are not covered in this post please contact Mendeley Support. Please check the blog and our social media accounts for any further updates.