Yesterday, the only vector processing tool I had was Open Street Map. After checking here, I re-installed QGIS and I had all the processing tools.
This morning, I have been using Geometry tools. When I deleted the layer I had created using Export/Add geometry columns, several processing tools, including Geometry tools, had disappeared.
I closed down QGIS and re-opened it and they were all back again.
Has anyone any idea what is going on please. It is annoying to have to close down and restart to be able to use a particular tool.
Best Answer
Some tools disappear when you reinstall QGIS. It's a bug, you can check it here: Built-in tools missing from Vector menu. I got the same problem, deleting .qgis2 folder I solved this issue.
Try to do the same, but be careful, python plug-ins are in the same folder. If you don't want to lose them, make a backup and restore them in new .qgis2 folder (will be created after QGIS start).