Maybe a broken/damaged instrument.

Nothing you mention is normal so if it is still or warranty you should return/replace it.

Is this consistently repeatable? Or did it just happen once or every now and then. Intermittent problems are the hardest to track down.

There are some things you can try or do while you wait to hear from the retailer though we have no idea if they will be of any help. It can be tempting to skip some of these since they can be tedious. But the more thorough you are the better.

POWER OFF inspection

1. unplug and remove all cables from the instrument

2. inspect it throughly for ANY signs of damage: dents, scuff marks, discoloration. Reinspect the shipping container if

you still have it.

3. look closely at all buttons, keys, sliders, knobs to see if any of them look out of place, misaligned, cockeyed, etc.

Inspect the ports/plugs on the back as well.

4. Tilt the instrument in various directions and listen for anything loose inside moving around. You can even shake it gently and turn it upside down - you are checking for any noise like something moving or loose.

DIAGNOSTICS

You can enter diagnostics mode by holding a C#2 hcord (C#2, F2, G#2) when you turn the power on. When you see 'Yamaha' on the screen you can release the chord.

There will be about 39 different tests that you can perform using the data dial to select each one.

Make a written note of any test that fails so you can provide that info to your dealer or service center.

POWER ON tests

1. Do a factory using 'Initialize All Data' on the utility screen. You may want to try to create a backup/user file first.

2. AUDITION the default/boot performance - does it work/sound properly?

3. Check each of the 4 'Init' performances - do they work/sound properly?

If you still have issues when absolutely nothing (cables, pedals) is plugged into the instrument you need to have it replaced or serviced to find out what the trouble is.

Longshot - but check that your M is the corrects voltage for your location.

Don't know where you are located or where you are using the instrument but you might want to double check the label on the back of the instrument and make sure it is the correct power/voltage for the location you are using it in.

MODX has a version 3.01?  Maybe the version that gets installed is different than what they list online but the online version currently shows version 3.00 for the MODX M.

https://usa.yamaha.com/support/updates/modx_m_os_updater.html

Surely Yamaha wouldn't actually let the Modx M try to install a Montage M update would they?

That would be weird! Especially if the user was using the incremental Montage M V3.01 which is only 75.4MB. There is quite a gap between the original Modx M OS and OS 3.0 and the incremental OS assumes you already have the bulk of the 3.0 functionality.

I think it's a typo (either Yamaha's typo or the OP).  I don't think it's a smoking gun of anything.  But I wanted to clear this up just to make everything make more sense.   Usually there's a sub-minor version that isn't always listed in the firmware download pages.  Like 3.00.1.   So that may be all this is.    Although looking at someone's video who updated, I see they went to 3.00.9.

At any rate - just want to clear the air.

We know from another user that they were trying to update their MODX M with Montage M firmware and it didn't let them.  So if Yamaha was doing this as expected these would be signed with signatures and encrypted with keys specific to the instrument they're getting installed to and attempts to verify the certificate and decrypt the firmware would fail.

And I guess there's a chance that some version 3.01 "leaked" and was pulled from the website after finding some bugs.  I don't think this happened either - but again worth checking for aligment with what's in the latest download section.

1. OS = 3.00.9 (installed January 14th)
2. I've done a hardware test (CIS Majeur chord on C2) and everything PASSED. So no RAM, ROM or CPU error?

The freeze was a one time only so far. Thoman suggested to return the M8 but I doubt if it's a machine error! It's mostly software and I think the OS is not 100%.  The loading latency problem is also software IMHO. After changing between performances the system is too slow to load everything. Sometimes (not  always, that's part of the problem) and the response from key pressing is not (completely) processed.

So I hope Yamaha takes this serious and works on a 100% firmware version. I think I will monitor the situation in the coming days, weeks or longer. Guarantee is long enough. I bought my M8 in december 2025 @ Thomann. Btw, I live in the Netherlands.

You might consider recording some videos, uploading them to YouTube, then post on Ideascale linking the videos asking Yamaha to fix the problems shown.  That would likely get the best traction.

Seriously consider returning the instrument.

Thoman suggested to return the M8 but I doubt if it's a machine error!

That is a generous offer since you are beyond the typical 30 period. Returning it now removes the burden, and cost, from you. If you don't return it any future occurence will be at your expense as well as the time, delay and cost, of getting it to a service center.

Your only 'risk' in returning it is if you have to wait for Thoman to supply a replacement unit. No doubt that in Europe that can be a big unknown.

It might be worth your while to ask Thoman when you would be able to expect a replacement unit before making a final decision about returning it.

Intermittent problems are the hardest to find and fix. Just because it passed the tests doesn't mean there isn't still a problem.

The problem could be temperature related, perhaps do to a poor solder joint. The problem could be a cracked circuit board that manifests when the instrument is stressed by being lifted or moved.

Only you can decide the amount of risk you want to assume.

I would still document the issue with video recordings if you can reproduce the problem(s).

Hello,

Sorry you are having issues with your MODX M8. Have you reached out to tech support here? If not, I would recommend contacting them.

In order to find out what's going on we would need more information. Please provide as much detail as possible about the circumstances involved like:

• What specific sound(s) were being played?
• Describe in detail what exactly is happening, like what do you mean by "loading latency", and what exactly is happening when you change Performances? As suggested in the thread, a video will help. If you would like to record and upload a video let me know and I can provide an upload link. 
• Was there specific user or library file installed? If so, we would request the the backup file to check.
• Was your MODX M8 connected to anything else via USB or MIDI?
• Please screen shot UTILITY/Settings/System to confirm the OS version?