Here is command line results just ran. I ow have IDE 2.3.4 experimented with loading older versions. All 2.x versions are experiencing this error.
I did run IDE 2.x on a 2nd gen I3 with Win10 without issues; I can't exactly remember the IDE version. The machine died about 1.5 years ago 
I did run IDE 2.x on a 2nd gen I3 with Win10 without issues; I can't exactly remember the IDE version. The machine died about 1.5 years ago 
It is sad to lose an old friend, I am attached to this machine also.
It is good to hear that my old friend is not likely the culprit :^)
OK, update.
My genuine Arduino UNO R3 arrived today. And put it to the test.
Uploaded my sketch from IDE 2.3.4 it seems to run slightly faster, no "CLI Daemon offline" error, yet Serial Monitor is still giving me the "Not connected. Select a board and port to automatically connect." error. Looking at the driver, it is Arduino...
Thus, I must believe that the clone boards are not the issue. As they load the CH340 driver.
Any thoughts anyone?
I assume that the answer to my question in post 34 was No then?
Terrypin,
I do not have answer for that. Have not ventured to the 2.x threads, and did not see a reference to a thread. Can you give me a link to your referral please? Would be happy to look, point me in a direction please...
The Related topics are directly below this thread! Just scroll down.
TY, was unaware :^|
Hi, thank you for clearing that up for me :^)
Have read through those posts and did not find anything that helped. Seems the trouble listed in those posts are different than my experience.
Have acquired a newer PC with Win11 loaded. About to delve into getting it set up and networking this machine with it. All that will be a new adventure (the networking part) for me.
Update: On Win11 PC here, installed IDE 2.3.6, still have CLI Daemon offline error.
Have not loaded sketch to check Serial Monitor yet.
Did find on a search with AI description rendered this:
If the Arduino IDE 2.3.6 shows the CLI daemon as offline, ensure that no other applications are using the required port (usually 50051) and try restarting the IDE. If the problem persists, check your network settings, as the IDE may need to communicate internally even when offline.
Will work at this a little later. Just wanted to update here.
Thank you to everyone for your input.
The TCP port used for communication with the "CLI daemon" via localhost is not hardcoded. Arduino IDE lets your computer choose an available port.
You can see the port used in this part of the output you shared:
From this, we can tell that port 55809 was used during that particular session of using the Arduino IDE application (it might be different from one session to another).
This makes it less likely that an accidental conflict with another application's use of the port could interfere with the communication. But it is worth considering.
In fact, during the beta development phase of the Arduino IDE 2.x project the port was hardcoded to 50051 and a significant number of users did have that exact problem, which was resolved once we changed to the current system of port assignment.
Thank you for this info. That would indicate that the info I got was old and outdated. Still not finding the issue :^|
Having some difficulty with the new PC, seems the OS is unstable and gets to a non boot status. Working on that...when it rains, it pours!
Will follow up when an update is available.
Update: Using Win10 on newer PC (Win11 was unstable for some reason, would lose internet connection, then on reboot would not boot, only solution found was to reinstall OS, after 3 rounds of this Win10 was installed and all seems good. will update to Win11 when available) and IDE 2.3.6 is running smoothly.
On older PC (this one) IDE 2.3.4 CLI Daemon connects, yet Serial Monitor still fails to connect.
I contemplating this, the same OS on both machines, the same IDE on both machines, the difference is the machines are older and newer. It seems as though the machine or hardware within is the source of the conflict.
It seems like Win10 is working OK for now so there is possibly an argument for leaving things alone for now - "if it ain't broke don't fix it". So you could just wait and see how it goes.
However, what you describe here would give me cause for concern. An OS should not just suddenly fail to boot. Is this running on a hard drive or and SSD? Random problems like this sometimes point to a failing hard disk. On the other hand, if its installed on an SSD, then it might be worth checking and re-seating the SATA cable and the memory modules. Since you mention loss of Internet connectivity, it might also be worth checking the seating of the wireless card for good measure, but I think that is much less likely to be the source of these problems.
You also mentioned in your opening post that you had tried "cleaning of the registry". May I as what with? Most of these free so called Registry Cleaner programs are a waste of time and quietly install various junk that can cause problems.
Different board, different driver, but same problem which would tend to rule out the board and driver. Could you also confirm that you have ruled out the USB cable by trying a different one? (I whizzed up and down the thread and can see that xfpd mentioned it earlier, but didn't spot an update).
Agreed, however with end of support coming soon...
OS is on SSD M.2 2230 this is my first experience with this type of SSD. It is a slot on the motherboard and secured with a screw. Also re-seated the RAM cards, there is nothing on the SATA cable. After the first instance of no-boot, I had searched for repair solution (only to find the system would not enter repair environment) then attempted to recover and the system would not allow entry of Key. I then bought a new SSD and was able to recover through Dell (not sure how that worked, had not seen it bofore) and Win11 was reinstalled. After another scenario of similar instance, I decided to install Win10 (I have ISO on USB for that, Also set up ISO on USB for Win11 during the first round). Win10 installed and has not had an issue.
You also mentioned in your opening post that you had tried "cleaning of the registry". May I as what with? Most of these free so called Registry Cleaner programs are a waste of time and quietly install various junk that can cause problems.
I use (for many years now) Registry Healer and have not had any problems on my Win10 machines (even the Win10 install being discussed), I did read that Zone Alarm is not compatible with Win11 and have used it for long time. Upon the second round I did not install Zone Alarm, yet the problem was still there. I have checked for compatibility issues of my programs, the rest seem to be ok.
Different board, different driver, but same problem which would tend to rule out the board and driver. Could you also confirm that you have ruled out the USB cable by trying a different one? (I whizzed up and down the thread and can see that xfpd mentioned it earlier, but didn't spot an update).
Ok, the USB cable, it works on both machines (Ihave 2, my original Win10 and the new Win11 machine that is now running 10) and the Serial Monitor works on the original machine running IDE 1.8.18 but not 2.3.4 or any 2.xx. The cable works on the new machine (that was acquired as a 2 year old machine I inherited from my deceased father in law) running IDE 2.3.6 (runs the Serial Monitor without a glitch). I would think the cable is not an issue, however it is a 2 piece, the short blue cable that came with my clone boards and an extension. You mention that xfpd mentioned it. Not sure of the mention referenced ( beyond my level of understanding) could you expand on this?
I appreciate your input. This thread has encompassed a few issues, with the now Windows stability/compatibility(?) happening.
Just a brief mention in post #18. Not sure whether it was perhaps meant as a hint.
Hard disks deteriorate gradually, but SSDs, when they fail, they just die. Getting rare to find hard disks nowadays. All modern stuff uses SSD, but was just exploring the possibility of file/data corruption due to iffy hard disk. Seems that's not the case here then.
Have had system issues in the past in the old hard drives, and reused the hard drive for extra storage. Was looking into a device on Amazon to add 2 SSDs
and possibly re-use the original SSD for storage. Would you think it would be worth while?
An OS should not just suddenly fail to boot.
I have not had this problem before (have been a PC user for 25 years, and have some experience in diagnosis/repair yet not extensive in the programming. Have not done much with Win11... this is my second PC with the system, the first, also inherited, is in use for my wife. That one was reconfigured with Win10 (I do not like Win11) and ran for a few months without issue, then updated to Win11 when it was reassigned to my wife for her use. It got the work arounds to have the look and feel of Win10 and is running very well. Just not sure why this one has been this way. It ran with the configuration as received, did the work arounds for Win10, then Firefox would not connect, had ethernet connection, Edge would connect, went on the search for the problem, reboot was required in the process, then when reboot occured, the system failed. The second round was similar with less tweaks taking place and when internet connection failed, Edge would not connect either plus ethernet connection was lost.
Any ideas?