Kanboard 1.2.7 cannot view attachment, but download is okay


Hello all,

I am assisting a project to upgrade kanboard 1.2.5 to 1.2.7.
After the upgrade, our user reported that he cannot view
a previously produced attachment, but can do so on a newly created attachment.

In checking my notes, I realised that I have not copied the attachments
from the old folder /var/www/html/kanboard-1.2.5/data/files/tasks to

Having rsynced the attachments, and restarted the web server, I can now download
the attachment, and open it for view. But when I click on the “View file”
option on the attachment, it opens a new window, displays a blank page.
Again, I can choose the “Download” option to save it as a file, then open it to view is fine.

I did check the /var/www/html/kanboard/data/debug.log, it only shows two errors:

[2019-01-08 11:42:22] [critical] GroupAssign: Unable to load this plugin class: \Kanboard\Plugin\GroupAssign\Plugin

[2019-01-08 11:42:22] [critical] Group_assign-master: Unable to load this plugin class: \Kanboard\Plugin\Group_assign-master\Plugin

There is no file under plugins/GroupAssign/, just an empty folder and
plugins/Group_assign-master contains the unzipped files from Group_assign-master.zip:
root@proj data]# ls …/plugins/Group_assign-master
Action _config.yml Filter LICENSE Plugin.php Schema Test
Assets Controller Helper Model README.md Template

Not sure these errors are relevant to the pdf attachment viewing though.

Any advice will be much appreciated.



Those errors are unrelated, and will go away if you correctly install Group Assign plugin.



Looks like I have resolved the issue after restoring the thumbnails files
under data/files as well as the task files. Somehow without them,
no PDF file is displayed.

As to the two “unable to load plugin class” errors, I removed
the two folders plugins/{GroupAssign,Group_assign-master).
The errors then disappear from debug.log upon a restart.
It looks like I have wrongly assumed installing the Group_assign-master
plugin by placing the unzipped contents into these folders.
The process I used to install kanboard_plugin_metadata-master.zip
and Subtaskdate-master.zip seemed to work okay though.


Best way to install them is through the Kanboard interface.

Manually, they ALL need to be in the appropriately named folder.