An invalid response was received from the device?

Detrich wrote:

Yes, but the re-download option only works if you've already downloaded that specific OS version in the past. As I stated in the post: All of those conditions imply that the OS was installed at one point on the machine.

So, if you happened to forget to download it or maybe skipped it, then Apple doesn't allow you to download it again- ever. Some customers may have very specific reasons for not being able to run the latest version of Mac OS X. Or, they don't update their machines for a reason. Or, they may have a need to download and run an earlier version of Mac OS X that -is- still supported for their hardware, but just not the latest version. And, what Apple has done is basically made it very difficult. Why would you need to go backward to an OS X that you never installed before?

Back in the pre-Mac OS X days You mean 2000 and earlier?, Apple made their entire OS library officially available in many different places on the internet- ie official Apple's web site, Apple's FTP sites, Apple's Hotline server (for those who remember those) etc etc. And, customers knew that non-supported OS versions are "non-supported," and that's fine... But, everything is so strict now. It's not as friendly and easy as before...

Sorry, but things and methodologies change. Apple does not allow you to downgrade to an OS you have never run before, but if you want to downgrade back to one of the ones you have, then you can do so.

Apple does not want people upgrading from a lower OS (like, say, Mavericks) to one of the intermediary ones that have been surpassed by a more current OS. So, they don't want to make Yosemite or El Capitan available for upgrade now that Sierra is out.

As for users that are still running on OS X Snow Leopard, Apple has provided a path via El Capitan in order for them to upgrade to Sierra.

http://www.apple.com/macos/how-to-upgrade/

Best of luck,

GB

You are currently running Snow Leopard. The article below provides links so you can see if your Mac's hardware is capable of running Sierra. If it is, then in the same article is a link explaining how to upgrade to El Capitan first, then to Sierra:

https://www.apple.com/macos/how-to-upgrade/

Best of luck,

GB

Yes, but the re-download option only works if you've already downloaded that specific OS version in the past. You must have at one point in time downloaded that specific version of Mac OS to your Mac via the App Store. Otherwise, you're forever locked out from downloading it ever- permanently. And, only the latest version is available.

So, if you happened to forget to download it or maybe skipped it, then Apple doesn't allow you to download it again- ever. Some customers may have very specific reasons for not being able to run the latest version of Mac OS X. Or, they don't update their machines for a reason. Or, they may have a need to download and run an earlier version of Mac OS X that -is- still supported for their hardware, but just not the latest version. And, what Apple has done is basically made it very difficult.

Back in the pre-Mac OS X days, Apple made their entire OS library officially available in many different places on the internet- ie official Apple's web site, Apple's FTP sites, Apple's Hotline server (for those who remember those) etc etc. And, customers knew that non-supported OS versions are "non-supported," and that's fine... But, everything is so strict now. It's not as friendly and easy as before...

I had this problem too. My iMac is about 5 years old and wouldn't work with my new iPhone 5 due to an 'invalid response'. I upgraded to OS Sierra and it's running fine now. A bit of a ball-ache however is that i have found I've had to update numerous other apps in order for them to run properly with Sierra. For example I've had to update iMovies as the picture quality was terrible after Sierra was installed and also iPhotos no longer works (although Photos and Preview are fine and just as good). Definitely update to Sierra but be prepared for a bit of a nightmare when you find a string of other apps need updating. It's like fixing one problem only to create a series of mini-problems. All fixable but a lot of faffing about. Ironically these reasons were why I moved away from using PC's for media editing. Technology eh? Anyway hope this is in some way useful.

That's why I asked what version of iTunes you are running. You must be running iTunes 12.5 or higher, and to run that level of iTunes, you need to be running Mavericks or higher as your OS on the Mac.

What OS X are you running on the Mac now?

Cheers,

GB

After trying the steps listed and spending 4+ hours troubleshooting this error stumbled upon a fix that worked. The strange part is that I could backup my apps but not do a full backup.

Go to Settings > General > Reset > Reset Location & Privacy. Now when you connect to formerly trusted computers, the Trust alert will ask you whether you trust that computer. Click "Yes".

Hi. I have a brand new iPhone 7s and i get this response when I try to connect to itunes and I can connect to iphoto for pictures. my itunes is up to date on a Mac OS X 10.7.5. I tried different cables and different USB ports: same result. When I connect my work iphone 6s, i get the same result as above. Any ideas?

That's because a device running iOS 10 requires the current version of iTunes, which requires OS X 10.9.5 or higher.

You're going to have to upgrade OS X or buy a newer machine if that one isn't capable of running at least 10.9.5.

For the last time...

a device running iOS 10 requires the current version of iTunes, which requires OS X 10.9.5 or higher.

You're going to have to upgrade OS X or buy a newer machine if that one isn't capable of running at least 10.9.5.

iTunes v.12.6.1.25

I upgraded to Sierra. Still got the same message.

Unplugged. Reseated. Unplugged. Reseated. Tried New Cables. New ports. Finally, at random. With no pattern I could possible reproduce it worked.

The truth is Apple doesn't know what causes this, and they have been content to let this issue sit there and fester and push it back on to the users to figure out for themselves.

Well, glad you got it to work. Agreed, it is one of those problems that is hard to reproduce since it is so intermittent. Several releases ago, when they added the new logic to check to make sure that the charger was Apple-certified, my Apple Cables would get the "This cable or accessory is not certified and may not reliably work on this iPhone" message. (eyeroll). I would unplug, replug, unplug, replug (slowly, not jerking anything), and after several tries, it started charging away.

It didn't happen every time, and I could discern no pattern as to when it did. A software update at some point must have fixed it, because it hasn't happened in a very long time now.

Computers - whadda gonna do?

GB

Apple makes excellent software. The problem is your computer. Which is probably running Windows.

This error usually means there is a USB timing problem in your computer. If you are using a USB hub, don't. If your computer is not a laptop and you are using a USB port on the front of the computer, switch to a port on the back of the computer. If you have other USB devices connected disconnect all except mouse and keyboard. Reboot your computer just before trying to connect. Disable your antivirus temporarily. Install the latest version of iTunes.

Try a different computer.

It can also mean that your phone is jailbroken, but if that's the case you can't get help in an Apple forum.

From this support document http://support.apple.com/kb/TS3694

iTunes cannot connect to the iPhone because an invalid response received from the device

This error occurs when there are problems communicating through USB. This may be resolved by following the steps for errors 13 or 14 above.

Error 13, 14, 35 and 50 (or -50)

These errors are typically resolved by performing one or more of the steps listed below:

1. Perform USB isolation troubleshooting, including trying a different USB port directly on the computer. See the advanced steps below for USB troubleshooting.
2. Put a USB 2.0 hub between the device and the computer.
3. Try a different USB 30-pin dock-connector cable.
4. Eliminate third-party security software conflicts.
5. There may be third-party software installed that modifies your default packet size in Windows by inserting one or more TcpWindowSize entries into your registry. Your default packet size being set incorrectly can cause this error. Contact the manufacturer of the software that installed the packet-size modification for assistance. Or, follow this article by Microsoft: How to reset Internet Protocol (TCP/IP) to reset the packet size back to the default for Windows.
6. Connect your computer directly to your Internet source, bypassing any routers, hubs, or switches. You may need to restart your computer and modem to get online.
7. Try to restore from another known-good computer and network.