Make sure you have Mach configured for Safe Z, its from Config menu.
I prefer to use SafeZ as Machine coords, that means I always know exactly where it will go. Z0 in machine coords should be fully up and all Z moves from there are down and negative. So if you set Safe Z as machine coords 0 or -.5 or similar then Z will always raise to that point when doing RFH or Go To Zeros.
You can also set safe Z as an incremental move or work coords move but as said I think machine coords is preferable.

Anyway, RFH, it will only work if licenced, I believe you are so thats fine.
To do RFH you select the line of code you wish to start at, you can do it by scrolling through the code window or selecting a line, doesnt matter.
Once you have chosen where you want to restart you press RFH and Mach will run through the code and then tell you to press Start when it has finished running through it. You press Start and then a prep move box will open, check the coords look fine and you can then press OK, Mach will move to the position detailed in that box but will observe Safe Z, ie it will raise first, move X and Y then lower Z. Once that has happened you can then again press Start and it will continue.

Few things, best to select a start that has Z above the material if possible.
If you have an ATC or use height offsets it is best to start at a tool change or make sure you have the correct tool and height offset loded by MDIing it prior to the RFH.
The prep move box has an option to Start Spindle, you need that chosen. Also you need to have a value in the spindle speed DRO as the spindle will only get a M3 command and no Speed command.

Hood

Righto I think you just fixed my problems.

I have not done anything with the safez setup.  I have seen it in the config but didn’t know what it did so left it alone.

I will check out what is going on there.

A the moment the prep move is to z- then to xy. Once at the xy position z will raise up and then it will ask to press cycle start and the spindle will start and machine will run.

Will report back once I get a chance to get into the shed. 

Sorry to hijack the thread but just thought it was sort of on topic so chucked it in this thread.

Ok I just set my safe z to -0.5 Mach co-ord.
Didn't have a lot of time to stuff around with it but did a rfh and it moved to z -0.5 first then xy. Then prompted for cycle start. So far looks to work a treat. Thanks a bunch hood

RFH has always worked well for me, once you understand how it works then its a great tool
Hood

Hey Guys, I am back two years later and still cannot get the RFH function to work. Its still reverting back to line 12 on all my gcode when I hit the RFH button. I have tried the settings last mentioned and nothing changes. Any more ideas?

attach your xml and some code and I will see if I can replicate your problem.
Hood

Here is the file

He asked for g-code and your Mach3 .xml
the .job file from your CAM program is useless.

okay sorry. I went back a tried to attach the xml but it won't let me since I posted the same name xml further back in the thread.

just rename it, or zip it with a unique zip file name.