Exporting Gerber files with Altium 18 and up

 Step 1&2: After opening your project file, open the aisler.OutJob file in Altium. You can find the aisler.OutJob file here: https://github.com/AislerHQ/aisler-support

Step 3a: You'll be confronted with a screen where you can see [PCB Document] under the "Fabrication Outputs" tab.

 Step 3b: Select your PCB Document as source.

Step 4: On the right side of the screen click 'Change'

Step 5a: A window will open where you should click on the first part of the path.

Step 5b: In the window, click 'Manually Managed' and then click the directory symbol. Choose a directory and close the dialgoue.

Step 6: Click 'Generate content'. This will export your Altium files to Gerber.

Step 7: In the chosen directory, you will find a folder with a time-stamp. That's the export folder

Stp 8: Right-click on the file and select 'Send to' -> 'Compressed (zipped) folder'.