Max/MSP 5.1.9 - Windows XP - audio error after authorization

Hi everybody,
I really hope that someone has had the same problem in the past and might still remember how to solve this.

I still use Windows XP for some art projects for artistic and practical reasons.

I properly authorized Max 5 with the challenge response cycling 74 sent me. I am an experienced Max 5 user and instructor, I use it since 2008. I have installed Max 5 during the past 16 years on several laptops and it has always worked, but not this time.

Here the problem I have:

• I installed Max 5.1 on a brandnew SSD hard-disk with a freshly installed version of Windows XP SP2

• Max 5.1 was working perfectly in „Demo“ mode

• AFTER I authorized Max 5.1 with a valid challenge response audio stopped working properly

• The problem: when I "turn off" audio (for example by sending stop to dac~ ), it cannot be turned back on and will be mute until I close Max and restart it! I tested this also with the cycle~ help file.

• When I do the same procedure in Max Runtime it works perfectly. So in Max Runtime I can open and close [dac~] as often as I want, in the authorized Max version audio playback will stop after closing and opening [dac~] or when I create or delete an audio connection (cable).

So it seems to me this is an MSP authorization issue! But what's the solution?

I made a demonstration video to show the problem that occurs after authorizing Max/MSP: https://youtu.be/x892Eox818o

There are several users that reported the same problem in the past so it seems a common problem at least years ago:
https://cycling74.com/forums/turning-audio-off-in-max5-breaks-sound-output
https://cycling74.com/forums/audio-issues-with-max-5

My system specs:

• Thinkpad R60

• Windows XP SP2 on a Kingston SSD hard-disk (to make sure the problem is not caused by the SSD drive, I tested the same setup also with a conventional Hitachi HDD, however, with the same devastating “audio error” result)

• Max/MSP/Jitter 5.1.9

Any help greatly appreciated!

Best regards,
MoTi