I created a thread in the past about this issue but nothing helped. Currently I'm using the machine as a (very expensive) milk steam and brewing with a Flair Espresso Maker. Is my MCaL destined to be nothing more than a milk steamer, or is there something I could actually do to fix it?

Without being there, there is no way to tell why it is really coming loose... My McAL used to do that too. I can offer only
these observations:

• Ensure your group to portafilter gasket is clean.

• Ensure your portafilter top ridge is clean.

• Are you locking it in tightly (this was my problem, I was scared to put it too tight). Remember, it is only friction holding it in.

• Is your grouphead pressure too high (e.g. are you grinding too fine?)

You should be able to rule out the last note with a measurement of your extraction volume vs time.

Again, mine came off a few times in the beginning. At first, I just held the portafilter with one hand and pulled the lever
with the other hand. I mean, you are not going to steam milk while it is extracting. After a while, I noted that when I put it on
tightly (I mean tight), it did not come off in my hand again. Since then, I have never held it while extracting a shot.

Let me define tight. I have to hold the base of the McAL while tightening it, or it will turn the machine. I tighten mine
right up to that point where I am forcefully holding the machine down on the counter thinking "this is obviously too tight".
That's about the right spot.

Hope that helps some.

I was actually steaming while brewing in the first 5 years I had the machine, and didn't have any issues.

I like your description about getting to the right tightness. I'll try that and will also follow your other suggestions.

Thank you so much!

Why not just hold the portafilter handle during the pull?

I prefer to have both hands free while brewing so that I can steam the milk without having to wait for the shot to finish.

Only saves 30 seconds!

I also had an issue with the portafilter popping off in the first month I owned it. I started tightening the portafilter way more (holding down the base as described in a previous post). Haven't had the issue since.

How old and used is this cranky Elektra? Apart from badly worn lugs or head the only reasons the P/F will/might pop out is a worn or wrong gasket or not being in tight enough. Can you try another portafilter?

Just as an aside. I had a Semiautomatica that did the same thing. It also had an o-ring type gasket which looked and felt fine but problem solved by replacing it with a new gasket.

I bought the machine 7 years ago and the problem started 2 years ago. The gaskets were replaced, but this only helped for a limited time. Maybe I should look for wider/thicker gaskets that use the same diameter (to increase friction)?

I have had the problem with my Sama, and I also like to steam while the shot is pouring. A new gasket should help. If not, you may need a thicker one.

But I also now usually hold the pf at the start of the shot, and begin steaming once the shot is about half done.