I get the message "the plugin will be disabled because it crashed QGIS during last startup." Which plugin? None is identified. I'm a bit of a rookie so not sure where to look to solve this. Running on a Mac with Mountain Lion, using QGIS Essen 2.14
It's the plugin processing.
QGIS 2.14 comes with a mechanism that deactivates plugins if they did not successfully load on QGIS startup.
This points out a potential problem in the plugin. Save your work and try to re-enable the plugin and if it fails to load again, file an issue (for the plugin, not for QGIS).
In its first version (2.14.0) there is a problem with this mechanism that doesn't recover the warning once the problem has been fixed.
To disable the warning open the python console, paste the following snippet and press enter.
from PyQt4.QtCore import QSettings QSettings().remove('/PythonPlugins/watchDog/processing')
Starting from QGIS 2.14.1 and 2.16, there is no longer a reason to use the python console. If the plugin could be loaded manually from the plugin manager the warning will be turned off (since this means that the plugin is actually safe to load).
It's the processing plugin.
It caught me out at first glance too, because processing is something that you think might be happening to any plugin as it loads.
On a Mac running MacOS 10.11.4 (El Capitan) this worked for me:
Download and install the latest QGIS. (Version 2.14.2 was posted to the download site around May 7, 2016.)
Launch the app and go to Plugins > Manage and install > Installed, then look in the list of plugins for one called "Processing" and check the box. Restart.
99% is that you upgraded qgis having an old installed version of Processing. Processing plugin is a core plugin and it's always availabe as core plugin, but it can be also installed via plugin manager (so intalled in $HOME/.qgis2/python/plugins/) so upgrade current core version.
try to: 1) de install processing plugin (if this is allowed means you have an installed version in $HOME/.qgis2/python/plugins/) 2) rerun qgis