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error - serial port COM4 already in use.

Thread starter #1
HI ALL,

Bought my first Arduino. It worked perfectly out of the box for about 15mins then stopped and now I constantly get serial port COM4 already in use.

I can't shake it. I spent many hours trying to fix it.

However it does seem to work on my desktop windows 7.

It refuses to work on my laptop windows 8 (but it did for a short while.)

I found the following link

http://arduino.cc/forum/index.php?topic=118321.0

but did not help me.

I upgraded to the new software Arduino 1.5.2, it did not help, I still get an error.

Does anyone know a simple fix for this?

Thanks
 

Ian Rogers

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#2
Where did you install the arduino software?.... If you have installed into "Program files" you will struggle.... If you move the whole directory into "Your Documents" It should work correctly.... Administration rights are a bit of a pain with the arduino software.....
 
Thread starter #3
Where did you install the arduino software?.... If you have installed into "Program files" you will struggle.... If you move the whole directory into "Your Documents" It should work correctly.... Administration rights are a bit of a pain with the arduino software.....
thanks for the reply Ian
well I was hoping for a simple fix - fingers crossed.
 
Thread starter #4
Where did you install the arduino software?.... If you have installed into "Program files" you will struggle.... If you move the whole directory into "Your Documents" It should work correctly.... Administration rights are a bit of a pain with the arduino software.....
my god man, i need to buy you drink like your avatar. it worked. i searched for hours and never found that solution. thanks again.
 

Ian Rogers

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#5
We had a young "work experience" lad in two months ago... He had a Windows 7 laptop. We installed the arduino software... When you select "Baud" ,"Com" etc... It cannot write the new settings to the config... So you only get it working once... After reboot... Again once.... I must admit it took me a while to sort it....
 
Thread starter #6
We had a young "work experience" lad in two months ago... He had a Windows 7 laptop. We installed the arduino software... When you select "Baud" ,"Com" etc... It cannot write the new settings to the config... So you only get it working once... After reboot... Again once.... I must admit it took me a while to sort it....
Perhaps that might fix my usb oscilloscope? I have a small usb oscilloscope that worked great in windows 7 but refuses in windows 8. Sadly the company that make it shut down before windows 8 came out I think, so I dont know if it's a driver problem or something similar to this.
 
Thread starter #8
You can still run devices in comparability mode .. You need to try running as administrator first....
well I fought with it for a while then gave up. it needs java to work. it refused to even work on windows 7. Then I uninstalled the java update and it worked again.

I will have to have another go of getting it work at some point. I do have a picoscope, but this one is a tiny usb stick type device. I liked it a lot.

http://www.youtube.com/watch?v=j1DfiEW6RV8
 

Ian Rogers

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#9
Uninstall it then re-install by using administration rights ( right click the install program and run as administrator)... Once installed run the application in the same fashion... You should only need to do it once..
 
Thread starter #10
Uninstall it then re-install by using administration rights ( right click the install program and run as administrator)... Once installed run the application in the same fashion... You should only need to do it once..
Thanks for the reply Ian

I found the problem. when installing the driver I got The hash for the file is not present in the specified catalog file. The file is likely corrupt or the victim of tampering.

I was thinking I need a windows 8 driver. In fact I found a page with a driver. CP210x USB to UART Bridge VCP Drivers. http://www.silabs.com/products/mcu/Pages/USBtoUARTBridgeVCPDrivers.aspx

But could not get it to install.

Then I found a solution that disables Windows 8 checking of the driver's signature


From the Metro Start Screen, open Settings (move your mouse to the bottom-right-corner of the screen and wait for the pop-out bar to appear, then click the Gear icon).
Click ‘More PC Settings’.
Click ‘General’.
Scroll down, and click ‘Restart now’ under ‘Advanced startup’.
Wait a bit.
Click ‘Troubleshoot’.
Click ‘Advanced Options’
Click ‘Windows Startup Settings’
Click Restart.
When your computer restarts, select ‘Disable driver signature enforcement‘ from the list

It now works! (The driver installs)

Shame I could not get the windows 8 drive to work. Any clues?
 
Last edited:

Ian Rogers

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#11
I have no experience with Windows 8 at this time.... I probably willl have to get used to it with my next laptop upgrade( due anytime now)

Until then I can only assume that the admin rights are the same as 7..
 

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