I've been using 2.0.0 b5 to get familiar with programming, and managed to get into a state where there was no USB comms - probably my fault, so I uninstalled the IDE and cleared references in the registry - just in case!!!
The IDE was then re-installed from the .zip file into C: root directory. No problems there and the IDE started with a blank sketch. Then I installed AVR boards 1.8.2 and selected a Micro on COM8. Finally I opened an existing working sketch.
This compiled fine but would not upload - until I discovered that a second copy of the IDE had loaded with the working sketch, but the comms were still firmly attached to the original blank sketch. This copy had to be deleted before the working version would allow upload and comms. Confusing to the uninitiated to say the least - perhaps a warning should be flagged up here!!
Final problem is the swapping of comms ports when an edit is made and an upload requested (the intended upload fails of course!!). In my case it changed to from port 8 to port 3. Changing it back manually still doesn't restore comms, so I am again faced with another remove and reinstall sequence unless I can discover a fix.
Update:-
After several changes to the physical USB port used, and changes to the virtual port selected, eventually comms sprang into life again. Afraid I did not note the exact sequence of operations - but at least it does seem possible to recover the situation. VERY frustrating - the IDE is virtually unusable like this!!
Why do you IDE 2.0? It's still in beta so problems are to be expected. If you need something that basically works, download IDE 1.8.13 (not the store version).
Downloaded IDE 1.8.13 as you suggested (used the .zip but wasn't sure what you meant by "the store version"). Ran into very similar problems only more so!! Possibly there is something amiss with my PC (Win 7 Pro), but everything else seems to be operating normally. All very frustrating.
I think some light is beginning to dawn!! My laptop has a USB mouse attached on COMM3, and when I ask for an upload, the IDE port switches immediately to COMM3 from whatever it was previously set to. Maybe this happens because the Arduino board looks like a keyboard and mouse (so I read somewhere). No idea what the solution to this might be - if there is one!!
Can you post two screenshots of the device manager; please don't post a screenshot of the complete desktop.
Normal; should look like
After a reset of the board; should look like
Next, in the IDE in file -> preferences, enable show verbose output during upload and disable show verbose output during compilation and try to upload a sketch and post the fullresult here.
Not sure why you have a USB mouse on COM3; nothing in my screenshots above. My device manager for HID related stuff (just FYI)
Checked again and sure enough the mouse appears as an HID device!! So I wonder what what COMM3 thinks its linked to - must investigate that and prepare the screenshots you requested.
So this upload seems to have been successful. Now what does the system show when it fails to upload? Images and verbose output please.
PS. If you disable verbose output during compilation, the output will be smaller and your can post it in your reply; please use code tags for that so it's easy to copy.
I've made some progress towards reliable operation - I think!!
The PCI serial port on COMM3 bothered me, so I disabled and uninstalled it so that it appeared under "Other devices". Finally I reinstalled it with a driver from the Dell drivers folder, and it now appears under COMM22.
Now when "Upload" is requested with COMM8 active, the green led flashes during upload and there is no output to laptop screen until led flashing stops - then port changes to COMM5 and simultaneously output to screen starts. Note - COMM5 is now the lowest numbered port - previously it was COMM3. Coincidence??
Ctrl + shift + M twice does nothing until port changed back to COMM8, then print statements appear as programmed. This process has been repeated several times with different "mickey mouse" programmes, and works 100%. COMM port swap seems to be a bug in IDE 2.0.0 b5