How do I activate "Open GRASS tools" button?

Question

I have opened two GRASS layers and need to use the "Open GRASS tools" button. This button remains unactivated somehow, while the "Edit GRASS vector layer" right next to it works perfectly fine. What can I do?

Answer 1

Below steps explain how you can create a new mapset and work on it.

• Click New Mapset Icon Or Plugins -> Grass -> New Mapset
• Browse to a new Empty folder to set it as database. Click Next.
• Select Create New Location radio button and Enter a name for it "GrassLocation" or something. Click Next.
• Select project radio button and Select your Coordinate System(like "WGS84"). Click next.
• Accept default values for grass region. Click Next.
• Enter a name for mapset (like MyNewMapSet). Click Next and Finish.

Now your grass tools should be active.

Answer 2

The toolbox only works when you have opened a mapset. This can be any existing mapset or you can create a new one as suggested by vinayan. However, note that all functions will use the settings of the opened mapset (extent, raster resolution).

Answer 3

Try changing your Custom paths in Grass Options>General to:

/Applications/QGIS.app/Contents/MacOS/grass7

Steps:
1. Click Plugins;
2. Click GRASS; 3. Click GRASS Options->General ->Custom;
4. Fill in: /Applications/QGIS.app/Contents/MacOS/grass7

Refers to this post: Set QGIS 2.18.7 on OSX - 10.12 to use GRASS 7

Answer 4

Have you also opened the PERMANENT map set? You should be able to see it in the OPEN Mapset menu.

When I open a new GRASS map set I can add layers. But I can't open the toolbox until I have opened the PERMANENT map set. Then it becomes clickable. p.123 of the QGIS Manual discusses the PERMANENT mapset as the location for core project data, so is probably needed store data manipulated by the GRASS tools.