“A device attached to the system is not functioning” error is experienced when transferring photos and videos from your iOS device to your computer. It is primarily because both devices cannot properly communicate. Like many other common problems, you can solve this without professional help.
Here are the best fixes to “a device connected to the system is not functioning” error. But you need to know a bit of background first!
Why Do I Get the “a device attached to the system is not functioning” Error?
This error is quite old and was once resolved, but it seems to have come up and was noticed after the iOS 11 update. iPhone 7, 8, iPhone X, iPhone 11, 12, or iPad Pro are common iDevices that experience this error.
Come iOS 11; Apple changed its usual media formats from JPEG and H.264 to HEIF, short for High-Efficiency Image Format, and HEVC short for High-Efficiency Video Codec. These new formats give fantastic quality results at the expense of storage space. Also, these formats aren’t compatible with many devices, but Apple has a feature that automatically converts media files to device-compatible formats during transfer.
Now, the “a device connected to the system is not functioning” error pops up when a glitch occurs with the conversion.
Other reasons are –
- Bad USB cable
- iDevice wasn’t properly connected
- The computer USB port is faulty
How to Fix “a device connected to the system is not functioning” Error | For Windows and Mac Users
1. Restart your Windows

Restarting your PC has been known to resolve any issues.
- Tap the Windows button or click the Windows icon to open the Start menu.
- Click the Power icon and select Restart.
- Reconnect your device and check if the problem persists.
2. Update your Windows

Updates typically optimize the OS, change the interface, add or remove features, and fix bugs. Updating your Windows may resolve the “a device attached to the system is not functioning” error when copying videos; follow the steps below.
- Click the Windows button or icon to open the Start menu.
- Select Update & Security, click Check for Updates on the next Window to see if there’s an update available.
- Download any available update.
- Also, you can configure Windows to auto-update your device from the Advanced Options page.
3. Try a Different USB

As we noted above, a damaged USB could make the “error copying file or folder, the device is unreachable” message shows up.
Ensure you are using the recommended iDevice USB; better still, use the cord that came with your device. It would be best if you unplug other USB devices (you can leave out wired keyboards and trackpad), too, then try transferring again.
Your device being unable to charge properly is one of the clues that your USB cord is bad.
4. Use a Different USB Port

A faulty port could also be causing the “a device attached is not functioning” error.
Go through your USB ports and connect your device to a port that is compatible with USB 3.0 connectivity; these ports are typically faster and better and are often indicated with a thunder sign by its side.
5. Restart your iDevice

A simple iPhone restart could resolve this issue too.
For iPhone X and above:
- Simultaneously press any volume button and side button until the power slide shows.
- Slide it off. Allow it for about a minute, then press the side button to restart it.
For iPhone SE to iPhone 6
- Press the side button until the power off slider appears.
- Slide it off and allow it for a minute.
- Press the side button and check if the problem persists.
6. Update iTunes

Updating your iTunes can resolve the “a device attached to the system is not functioning when installing” error.
- If you got your iTunes from the official Apple website, launch the app, click on Help, then select Check for updates.
- If you got it from the Microsoft store, click the Start button or the Windows icon and search for Microsoft Store.
- When in, click on Downloads and Updates; it is hidden in the menu at the top-right corner.
- Go through the available updates there and download iTunes.
Alternatively, you can thoroughly uninstall iTunes and then download and reinstall a fresh version from Apple or Microsoft Store.
7. Download a codec

As stated above, the new media format (HEIF & HEVC) isn’t compatible with many devices, e.g., Windows. So, you’ll have to get a program to teach Windows how to access these files to tackle this.
Visit this link to purchase the HEVC Video extensions to access videos in this format or this link for HEIF Image extensions.
8. Convert the files using a third-party converter

If you can’t go with the above solution, you can use a third-party online tool to convert the formats to device-compatible formats.
Convert HEIF to JPG
Convert HEVC to Mp4
9. Free space on your iDevice

iPhones usually have ample storage space, but we could run out of it. When iOS converts the HEVC and HEIF formats to device-compatible formats, it consumes much space. Make sure there’s enough storage space –
- Open your Settings app, then go to General.
- Navigate to iPhone Storage. It shows you the different files and how much space they consume; delete unneeded data if you are low on storage.
10. Reset Location and Privacy

The device attached to the system is not functioning error is likely to occur when you don’t “Trust” your PC.
Now, on connecting your iDevice to your PC for the first time, iOS asks you to “Trust the computer” first; if you click No or something goes wrong, both devices won’t communicate effectively.
To resolve this –
- Unplug your device from your PC, then go to Settings and select General.
- Locate and select Reset, then tap the Reset Location & Privacy option.
This action would also reset every other PC you’ve “Trusted” in the past. When done, check to see if the problem persists.
11. Transfer Images in Original Format

Alternatively, you can transfer your media files in their original format. This solution goes hand-in-hand with solutions 7 and 8. I’ll recommend this if you can’t free up space on your iDevice.
- Open your Settings app on your iDevice.
- Tap the Photos options, then select Keep Originals under the Transfer to Mac or PC section.
12. Update iOS drivers

Updating your iOS drivers on your computer can resolve this issue too.
- Right-click over the Windows icon or use the Windows + X shortcut keys; from the pop-up menu, select Device Manager.
- Expand the Portable Devices option by clicking on it, right-click over Apple iPhone/iPad, and select Update.
- Follow the on-screen instructions. You can update the drivers manually or online.
13. Use CopyTrans Photo

CopyTrans is a third party that takes the load off iOS’ shoulders. It does the job of converting the HEIC files while using your PC resources. Since it’s more likely that your PC would have enough space than your iDevice, you can stop worrying about storage space on your iPhone.
Download CopyTrans from here.
Also Read: How to Convert Video to Audio on Desktop, iOS, Android, & Online
Conclusion
As annoying as “a device attached to the system is not functioning” is, we can efficiently resolve it. This problem is common in iPhone 7 and above, especially in the iOS 11 update. To tackle this issue, you can first restart your iDevice and PC, try a working USB or switch the ports; preferably a USB 3.0 port.
Also, you can convert the HEIC or HVAC format with a third-party online tool or use CopyTrans!
FAQs
Q. What does it mean when a device attached to the system is not functioning?
This means both the device and your computer are unable to establish communication. When you connect an iDevice for the first time, it requires you “Trust” the computer; not doing this could cause the error above although a bad USB cable or spoilt USB port could cause the same as well.
Q. Why can’t my Mac find my device?
This is often a USB issue; your USB might be malfunctioning. To resolve this, unplug all other devices except essential gadgets like keyboard or mouse, then try connecting your iDevice again and checking if the error persists. Finally, ensure you are connecting with a working USB cable or try a different USB port.
Q. How to fix an “a device attached to the system is not functioning” error on Mac?
First, ensure the OS is up to date on your Mac computer, then disconnect all other USB devices and reconnect your iPhone with a working USB cable. Also, restart both your Mac and iPhone, then check if the problem persists.Â
You can try the “Keeping Original” files format while transferring by going to Settings > Photos and switching on this feature under the Transfer to Mac or PC section.Â