USB not visible - why?

[Ubiquitous2024]

My desktop > phone connection is always intermittent, this has been going on for years with different phones and desktops. You get months of no issues whereby phone plugs in, files open on the desktop and you can transfer files / music whatever. Then for absolutely no reason whatsoever, it suddenly just doesn't work. Phone says "slow charging, make sure cable isn't damaged or defective" and it doesn't work. Absolutely nothing changes between it working and not working. Then you go through tons of different cables, try tons of different ports, but it remains invisible. Then suddenly at a random time in the future, it will work again?

I have been trying for 2 days now and still can't get visibility of my phone on the desktop,

Why does this happen?

[Mr Squarekins]

Might be stating the obvious, but I know when going the same, my phone has to be 'active'. If the phone isn't live with an active screen, my PC does not see it.

[lufbramatt]

Fluff in the phones charger port?

[Road2Ruin]

lufbramatt said:

Fluff in the phones charger port?

That would be my guess, too. Easy to over look.

[Mr Pointy]

If your PC has Bluetooth have a look at Quick Share:

https://support.google.com/android/answer/13801258...

Just note thatthe MS Store version might only work with Samsung phones.

[Gnits]

There are a few things that might be worth checking:
Are the cable connections worn?
Are you using the same cable each time? Some cables may do power but not data etc, or the other way around. How can you tell? Magic, there do not seem to be any standards on this.
When you plugged the phone it was the battery at 0%?
Windows will mess with USB in a number of fun ways - if a resource is not used it MAY drop that USB port, you might have to plug something else into that port to wake it up or reboot the pc. If you have unplugged the item from the port it MAY decide to never play with that device again unless you drop the port in Device Manager and restart it.

I have had many hours of fun with all of the above. The current one I am enjoying is the wireless mouse hilarity, if the mouse gets to 0% Windows will drop it. If I plug the mouse in it will then be recognised but will no longer be wireless even when fully charged until I uninstall the software and re-install it again.

[speedyman]

Sounds like power is the issue if the phone is getting messages about slow charging.
Ai derived below.
USB ports supply varying amounts of current depending on the version: USB 2.0 provides up to 500 mA (2.5 W), while USB 3.0 can supply up to 900 mA (4.5 W), and the newer USB Power Delivery (USB PD) can deliver up to 5A at 20V, equating to 100W.

[Ubiquitous2024]

But how and why then does the port work perfectly 500 times in a row, then fails at time 501, 502, 503 etc etc

[speedyman]

What was the percentage of charge left in the battery when it failed compared to when it didn't. If the battery is very low it initially would pull more current from the port than it can supply, hence the slow charge message. You can see the same behaviour when you charge a car battery. It's due to changes in the internal resistance of the battery from flat to fully charged.

[Road2Ruin]

Electricity is pushed, not pulled. So the device can't take more than the supply provide.

The usual reason for these occasional non connections or poor speeds, is a poor connection. Either fluff in the phone terminal, a poor cable, worn contacts, a contact that is bent, other devices on the USB (That's the bus rather than the port) requiring power too.