I am using QGIS 2.18 and have a workflow that requires going offline with some of the data. My workflow is fairly simple:

  • Go to Database - Offline Editing - Convert to Offline Project. Select the layers that will be edited offline.
  • Edit the offline layers are required.
  • Go to Database - Offline Editing - Synchronize

The sync process runs and is successful, but the result creates duplicate entries in the master (online) database for any of the features that were edited or created offline.

I have tried using SpatiaLite and PostGIS as my master (online, source, whatever you would like to call it) database, with the exact same results.

Any suggestions?

1 Answer 1


This is something that I have noticed recently when working on QGIS 2.14.9 LTR on a work machine, and 'offlining', and 'syncing' from, and to, a PostGIS database.

I have tried testing the same workflow and files on a personal machine running both 2.14.14 and 2.18.10 and the Offline editing works fine, I don't get duplicates.

So, although you haven't said which release of 2.18 you are using, I suspect that the problem will be solved by downloading the latest release of 2.14 or 2.18

  • I am using 2.18.9. I will try 2.18.10 and report back.
    – K. Hartman
    Jul 18, 2017 at 17:55
  • I have downloaded 2.18.10 and verified that the issue still exists. I have tested using PostGIS and SpatiaLite as the master database.
    – K. Hartman
    Jul 19, 2017 at 2:38
  • Ok. That is very interesting, when I tested 2.18.10 on my personal computer I did not get duplicates. This clearly needs more investigation - so my answer is not the answer. But rather than delete it for now, I shall leave it in the hope of looking into this and editing it with a solution. It is something that I need to solve for myself and about 10 users in a similar situation. From my previous trials I had assumed that it was a QGIS version issue. Jul 19, 2017 at 17:09
  • This may help. I created a very simple Layer in SpatiaLite that is a point with an autoincrementing primary key as the only attribute. I added 2 points while online and saved the Layer Edits and the points were assigned primary key values 1 and 2, as expected. Then I sent offline, added 2 points and saved the Layer Edits. They were not assigned any primary key value. After Sychronizing the changes the 2 new points had primary key values of 3 and 4 and duplicates were created with primary key values of 5 and 6.
    – K. Hartman
    Jul 19, 2017 at 18:37

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