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Have you checked for backlash with a Dial Indicator, as opposed to a dial test indicator which can be difficult to setup to negate any cosine error. T me this sounds like a backlash/leadscrew related issue.
Many times an similar issue has come up similar to this, even tho the user had checked the mechanical side, it turns out upon closer inspection it is indeed a mechanical issue. Coil type couplers aren't worth much as they can wind up. Don't rely on the stepper motor to provide any fixed bearing support (as many 3d printers and cheap chinese mills do), use angular contact bearings, the non driven end of a leadscrew should be able to "float" laterally to allow for thermal expansion.
Even ballscrews have backlash, unless you are paying alot and I mean alot for ballsrews expect some backlash.
Missing steps could also be a cause. But if I were a betting man I would put a wager on a mechanical issue. The thing regarding mechanical issues is they can add up, a little here and little there and another bit there can end up as a nightmare.

Here's a document far more eloquent than I could describe.
rick.sparber.org/mt.pdf

Once again can you please offer up the version of Linuxcnc,the underlying OS and whether you are using a parallel port based system with software step generation or you are using a hardware based solution, once again any config files will be helpful.

Call me what you want I really don't mind, as you don't know me personally it hasn't affect .

In my dealings with PCW I have found him to be very generous with his time, knowledge and the schematics related to his products. Like I said read the forums and pay attention to the advice, help and response to custom FPGA bitfiles for his line of Mesa products, you will find everything I said to be truthful representation of the facts.
If you require help we're here to help, if you want to argue I gladly indulge that as well. If you bear false witness regarding members of this forum I will refute any statements that do not truthfully represent their character.

In saying all that I feel this thread would be better off deleted as it is proving to be a tit for tat affair.

Mayhaps then you could start a new thread and we can forget about the whole MEM thing which isn't a "Linuxcnc concept" as per the standard codebase. If this was a feature the various GUI would have that button, Hal pins would be exposed for that feature and it would be documented.
The closet feature would be the "reload button" but that rereads the file from the filesystem, but will also use the the original filename with any changes that may have been made. Which when combined from the "run from here" feature is a useful way to add extra code to a file without having a complete rerun.

Once again, the I formation requested regarding your system will be most helpful.

I would like to request if this information isn't supplied that either the thread is locked or deleted.

youtube.com/

Is this a parallel port driven machine?
If yes, raise the BASE_PERIOD in the ini file to at least twice what you have now and test again.
Also, lengthening the step time and step space might help a lot.

Hey, I have a weird issue. Not sure where it comes from or what the cause is, but I don’t know what to look for anymore.My machine is off position at the end of the program. For troubleshooting: I put a work piece in my machine and went to X10 Y20 and made manually a mark on the workpiece.Then I run a program and at the end I go back to X10 and Y20, but the machine is off in X and Y for a few millimeter. This is happening again and again and it is always the same distance off. First I thought it had something to do with speed and acceleration. I tried lowering it. Same error. I let the machine then run in a higher Z position without any load. In the air so to say. Same error!Then I tried another NC program, same thing here. At the end it’s repeatable a little bit off.I lowered the acceleration (75mm/s2) and feed speed to 1/10 (600mm/min) of its original value. Same error!I had deadband at 0.01 and lowered it to 0.007. Same error.I tried changing the Ferror from 2.0 to 1.0. Same error.I tried different programs and it feels like the offset is larger if the travel within the program is larger.I checked the mechanics and I am sure it’s not a mechanical error.I don’t know what else to test.

The machine is an open loop stepper system with DM322T Driver and Nema 23 motors.

Thanks, how to turn it off?   Forgive me for being a newbie.

Nice find, and it does have a parallel port header and an M.2 slot.
But at 146 Euro here, i am skipping it for now, might go back to it later as it uses a single power supply, probably 12V adapter, and not the full ATX power supply.

What GUI? Assuming you are not using Axis as it is by default in Auto mode.
Does the machine use a tool changer?
Does it use any custom components?
Does it have any added hal wizardry?
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I recall a while back in certain states/conditions it would run through all the tools in the gcode, but it was probably fixed since for a long time it was not mentioned here.

Probably would need also changing the - sign for home_search_velocity and maybe home_latch_velocity for that axis/joint.

Helpful? I'm fairly certain you believe that too.
If there's confusion about something, then ask a question. No questions were asked. It's really easy too. "What do you mean by MEM? I'm not familiar with that term." I would have been happy to answer to clear up any confusion and learn whatever you folks call it.

What did I get in return? Some self-conceited person you consider an "esteemed colleague" that thought that I was too dumb to not know what operating system I was using...
Bad news, I match energy. If you don't like what you put out thrown back at you? Then don't be that way.

And here you are tossing out childish insults...

I'll figure it out myself.

Oh this old gem, the solution is to remove or purge the offending raspberry pi package. Its been mentioned many many times throughout the forum, the exact commands can be found with a quick search.

But the the theories above do not take into account it is fine afterwards, very intriguing.

It's quite possible it is a gcode issue, mayhaps the cam is in metric units and the machine is setup in imperial units and no g21 was given in the preamble.

Another possibility is whoever setup the machine gave the overrides quite a large postivie range and the feed override is set at max.

And just for clarity Linuxcnc loads the gcode from the filesystem, ie from disk, not from "Internal memory", for those that are familiar with computers there is a distinction between memory (being ram/rom) and disk. As many things getting terms incorrect can cause confusion.
Look for all we know you could be using a custom interface with a MEM button implemented to make the machine more familiar. If that is the case it would be no wonder there has been confusion. Reading through the documentation for the various interfaces supplied with Linuxcnc there is no mention of a MEM button. I mention this as the frustration of the OP seems to be the questioning of a MEM button being implemented in Linuxcnc to retrieve gcode from "internal memory".

I have just realised that my thingy requires you to type in the values. That's not as ergonomic as one might hope. Give me a few minutes.
Files updated
 

@scotta Following chatgpt it could work by only do ARR/CCR-updates via DMA-burst and the rest with timers. Does that make sense?