Installation failed: Can't install the software

I had the same issue. I started downloading but it gave me the not available error so i just clicked on ok but it kept downloading. you can check on itunes if its downloading or not by clicking on the arrow thats pointing down.

I had the same issue. Even after updating to the latest software, it still showed up.

What solved it was changing the lightning cable I used to a non-Apple store one that I had bought elsewhere.

It automatically connected.

I figured it out! I had been messing with instructions for about an hour. Sometimes my ipad would become visible for maybe a minute and then disappear and then I would get the message we all got and try and install software and NADA! Then I got the message about the server.

Soooooooooo, the easiest item for me to replace was the USB cable from my Mac to my iPad! Found the original I got with my Mac. Used it, and "BINGO" All is well. Got my iPad and Mac synced! I am a happy camper. No more buying low budget cables on ebay!!!!

1. Sign out and sign in into your iCloud in your phone.
2. May be thats bug just do not update from iTunes, go to phone software update.

And if your iMessage & FaceTime throws error in Sigin (See my answer somewhere in previous reply)

Fix 1:

The version of the iOS device may got expired. Check whether both the device are up to date. If not then update the device with latest version and try to sync the device.

• Go to Settings > General > Software Update.

If you still face the issue then follow next fix.

Fix 2:

It may cause due to the date an time mismatch of your device which you want to sync up.

https://techmazza.com/installation-failed-cant-install-the-software-because-currently-not-available-ios/

sort of...just be sure the time and date are set automatically in all your linked apple devices !

Try this two steps

How to reset the System Management Controller (SMC) on your Mac - Apple Support

and

Reset NVRAM or PRAM on your Mac - Apple Support

I had the same problem,

for me the solution has been to attach the USB cable to another port.

Apparently this is what worked for desertdragonlady...

https://discussions.apple.com/thread/8464414?answerId=34247353022#34247353022

You might try CMD+L keys to see if logging shows & offers any clues.

I had same problem. I was using extension wire. When I connected iphone directly, it worked for me.

My issue as well. Date and time set to automatically as they have been for years. Solution was the cable. I had an Apple lightning cable that was working fine until today (still works to charge from an outlet). Used a non-Apple cable from a convenience store that solved the problem. Weird that all these people had the same problem at the same time with cables that have been working fine until recently.

It's been a while for this post, just thought to share my experience, yesterday i had a call with Apple support with same issue. Yes, it started with new apple iphone Xs original boxed USB cable. I thought it was the cable for a while and when i switched back to my old iphone X cable it worked (I was able to connect my iphone to my Mac Book). Apple also, told me to charge your phone to at least 80% with the power plug and try with the new USB cable of Xs. Once i charged it to 80% it worked with my new USB Xs cable. Weird, because if you connect iphone to Mac it should charge as well. Looks like the new USB cable of iphone xs needs to be charged using wired power plug and then it connects to the Mac book. Hope this helps.

I used a different USB cable and works.

I have the same issue. Changed the USB port on the MacBook and it worked. Still doesn't work with the other USB port. Strange indeed and would for sure like to have this fixed.