How to Fix: Unable to open serial port error message

A serial port may be useful, but some users have reported that the serial port message cannot be opened on their PC. This can be a big problem, and in today’s article we will show you how to solve it.

Problems with a serial port can be very annoying, especially if you tend to use the serial port frequently. When we talk about these types of problems, here are some related problems that have been reported by users:

• Connection to com1 Windows 10, com3 could not be opened – This problem can sometimes occur if you do not have the required drivers. To solve the problem, you must update the serial port driver and verify that it solves your problem.
• Putty cannot open Windows 10 serial port – Sometimes this problem can occur due to some Windows services. This is not a big problem, and you can solve it by disabling these services.
• Access to the serial interface com1 cannot be opened – This problem may occur due to problems with the serial interface. To solve the problem, temporarily disable the serial port and see if it helps.
• Com port cannot be opened win error code 5, 123, 32 – These are some common problems that can occur with a serial port, but you should be able to solve most of them with one of our solutions.

Windows may try to assign it to a COM port already in use. It seems that Windows sometimes gets an inconsistency in the registry of what has already been assigned.

To see if this is the problem (and if possible solve it), try changing the assigned COM port.

1. Go to Device Manager > Ports (COM & LPT) > mbed Serial Port, then right-click and select Properties.
2. Select the Port Settings tab and click Advanced.
3. Under “COM port number”, try to select a different COM port.

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Note that Windows marks some of them as (in use), but does not consider them exhaustive, for the same reason that this problem may exist!

Try switching it to a few different unused COM ports and see if it has an effect. If not, we will dive deeper to see what Windows is reporting.

And don’t forget to unplug the power cord after the change to recharge the driver and see all the results.

Try using another cable.

I noticed that using an older USB cable sometimes leads to a poor connection of the card. It would be moody if it worked sometimes and not differently. The problem was solved with a new or even different cable.

Hyperterminal

If you enter “Hyperterminal” in the Windows Start menu, right-click after the call and select “Run as administrator”. It should help you access the serial port.

Also check which COM port it uses. To do this, follow these steps:

1. press the window+R button

2. type devmgmt.msc

Now check which port is assigned to the USE serial converter and use it in the spatula.

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FIX: Unable to open serial port

• Serial ports are the interface between a PC and devices that don’t support a Bluetooth connection.
• Driver errors or physical damage can cause your serial ports to become unresponsive. We’ve got some quick tips for that.
• To keep you safe, also take your time to check out the best software tools for blocking USB ports.
• This detailed article is part of our Windows 10 Errors Hub, so do not hesitate to bookmark it.

1. Download Restoro PC Repair Tool that comes with Patented Technologies (patent available here).
2. Click Start Scan to find Windows issues that could be causing PC problems.
3. Click Repair All to fix issues affecting your computer’s security and performance

• Restoro has been downloaded by 0 readers this month.

A serial port can be useful, but some users reported Unable to open serial port error messages on their PC. This can be a big problem, and in today’s article, we’ll show you how to fix this error.

Problems with a serial port can be quite annoying, especially if you tend to use the serial port frequently.

How do I fix a serial port that doesn’t open in Windows 10?

1. Make sure that you have the necessary drivers

If you’re getting the Unable to open serial port message, perhaps the problem is related to your drivers. To fix this issue, it’s advised to update your serial port driver.

To do that, you can visit your motherboard manufacturer’s website and download the latest drivers. If you find this process a bit tedious or complex, you can always use a third-party tool.

DriverFix simply is the best choice when it comes to updating all your drivers automatically, with just a couple of clicks.

It will keep your computer safe from downloading and installing the wrong driver version, which can cause serious malfunctions and ease the process.

DriverFix

2. Verify that the port isn’t open/disconnect the cable

Sometimes Unable to open serial port message can appear if the port is already open. To fix this problem, users are suggesting to disconnect the cable from the other device and try to connect again.

This is a simple workaround, but several users reported that it worked for them, so feel free to try it out.

3. Stop the Windows Fax and Scan service

1. Press Windows Key + Rkeyboard shortcut to open the Run dialog.
2. Enter services.msc and press Enter or click OK.
   
3. When the Services window opens, locate Windows Fax and Scan service and double-click it to open its properties.
   • If this service isn’t available, try changing the settings of the Fax service.
4. Set the Startup type to Manual and click the Stop button to stop the service. Now click Apply and OK to save changes.
   

Several users reported Unable to open serial port message while trying to use the serial port. It turns out that the problem was Windows Fax and Scan service.

To fix this problem, you just need to stop Windows Fax and Scan service. After doing that, check if the problem is still there.

Bear in mind that this is just a workaround, so you might have to repeat it every time you want to use a serial port on your PC.

4. Disable the serial port in Device Manager

1. Press Windows Key + X and choose Device Manager from the list.
   
2. When Device Manager opens, locate the serial port, right-click it, and choose Disable device from the menu.
3. When the confirmation dialog appears, click Yes.
   
4. Wait for a couple of moments and then enable the serial port.

If you keep getting Unable to open serial port message on your PC, the issue might be related to the serial port driver.

This is usually caused by a temporary glitch, and in order to fix the problem, it’s advised to disable the serial port temporarily.

Run a System Scan to discover potential errors

After doing that, check if the problem is resolved. If this solution works for you, bear in mind that you’ll have to repeat it every time you want to use your serial port.

5. Try using a different cable

Sometimes, the Unable to open serial port error can appear if your USB cable isn’t working. Be sure to check if your cable is properly connected. In addition, check for any visible damage.

If your cable seems to be in order, try replacing it and check if the problem appears with a different cable.

6. Restart the device

If Unable to open serial port keeps appearing, perhaps you can fix the problem by restarting your devices.

Simply restart the device you’re trying to connect to and check if that solves the problem. Alternatively, you can restart your PC and see if that solves the issue.

7. Reinstall the serial port driver

1. Open Device Manager.
2. Locate your serial port, right-click it, and choose Uninstall device.
   
3. Now click Uninstall to confirm.
   
4. Once the device is uninstalled, restart your PC.

As we already mentioned, sometimes issues with your serial port can be caused by your drivers.

If you keep getting Unable to open serial port message, you might be able to fix the problem simply by reinstalling the serial port driver.

After your computer restarts, Windows should install the default driver and the problem will be completely resolved.

8. Make sure that the system is up to date

1. Open the Settings app and go to the Update & Security section.
2. Now click the Check for updates button in the right pane.
   
3. If any updates are available, they will be downloaded automatically in the background and installed as soon as you restart your PC.

In some cases Unable to open serial port message can appear if your system isn’t out of date.

An outdated system can lead to various compatibility issues, and the best way to avoid these issues is to update your system.

This process is quite straightforward in Windows 10, and for the most part, Windows installs the updates on its own. Once your system is up to date, check if the problem is still there.

Getting the Unable to open serial port message can be a problem for many users that use the serial port frequently, but you should be able to fix this problem using one of our solutions.

Speaking of these kinds of problems, here are some related issues that users reported:

• Unable to open a connection to com1 Windows 10, com3 – This issue can sometimes appear if you don’t have the necessary drivers. To fix it, be sure to update the serial port driver and check if that solves your problem.
• Putty unable to open serial port Windows 10 – Sometimes, this issue can occur due to certain Windows services. This isn’t a major problem, and you can fix it by disabling those services.
• Unable to open serial port com1 access is denied – This issue can appear due to glitches with a serial port. Temporarily disable the serial port and check if that helps.
• Unable to open com port win error code 5, 123, 3 – These are some common problems that can appear with a serial port, but you should be able to fix most of them with one of our above tips.

Let us know which one worked for you in the comments area below.

Putty настройка подключения через COM порт

Меня часто спрашивают, как настроить подключение через COM (RS-232) порт в Putty.
Это делается очень просто. Сначала узнаем в диспетчере устройств номер нужного нам COM порта.

Для этого вызываем диспетчер устройств: Win + R->mmc devmgmt.msc->Enter

и находим номер, нужного нам, порта.

Номер порта

в моем случае это COM3

Теперь запускаем Putty и настраиваем его.

Настройка Putty

Connection type: Serial — последовательное подключение.
Serial line: COM3 — номер COM порта.
Speed: 9600 скорость передачи информации.

И нажимаем Open (хотя можно сначала сохранить, чтобы каждый раз не вводить).

Если все сделано правильно — поздравляю. Мы подключились.

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