[Solved] How do I fix iPhone “backup session failed” on iTunes?

Problem: iOS user complaining on the discussions.apple.com after encountered the iTunes backup session failed message when trying to backup or restore the iPhone on a computer using iTunes. Backup session failed is not only happened to a particular OS or iOS but also nearly all models of the iPhone. Even tried all the methods provided by Apple could not get this issue fixed.

The detail error message as below:

iTunes could not back up the iPhone because the backup session failed.

Follow below effective solution steps to resolve the iTunes backup session failed issue.

Content Summary

Potential Causes
Solution 1: Use other cable and port
Solution 2: Reconnect iPhone and Windows
Solution 3: Rename or Delete old backup
Solution 4: Reset iTunes Lockdown folder
Solution 5: Update Windows to the latest build
Solution 6: Update iOS to the latest build
Solution 7: Update iTunes
Solution 8: Allowing all Apple related processes
Solution 9: Temporary disable security applications
Solution 10: Add the computer as trusted devices
Solution 11: Repair iTunes
Solution 12: Reset iTunes
Solution 13: Reinstall iTunes
Reference

Potential Causes

• System glitches
• Incompatibility between the present iOS and the old backups.
• Backup is corrupted.
• Block by security applications such as Antivirus, Antimalware or Firewall
• Corrupted installation of iTunes
• Corrupted Windows or iOS

Solution 1: Use other cable and port

Try another cable and port to back up the iPhone.

Solution 2: Reconnect iPhone and Windows

Step 1: Exit all Apple applications.

Step 2: Remove the USB cable.

Step 3: Restart both PC and iPhone.

Solution 3: Rename or Delete old backup

Find the old backups on the computer, then rename or delete it.

If you installed iTunes from Microsoft Store, the old backup located at C:\Users\YourUserName\Apple\MobileSync\Backup

If you downloaded iTunes from Apple’s site, the old backup located at:

• Mac OS X : ~/Library/ApplicationSupport/MobileSync/Backup/
• Windows 10/8: \Users\USERNAME\AppData\Roaming\Apple Computer\MobileSync\Backup
• Windows 7: C:\Users\user\AppData\Roaming\Apple Computer\MobileSync\Backup

Solution 4: Reset iTunes Lockdown folder

For Windows:

Step 1: Exit iTunes and disconnect the iPhone from PC.

Step 2: Go to iTunes lockdown folder at C:\ProgramData\Apple\Lockdown.

Step 3: Delete everything in the Lockdown folder.

Step 4: Start iTunes and connect the iPhone to the computer using the USB cable.

Step 5: Tap Trust.

For macOS:

Step 1: Exit iTunes and disconnect the iPhone from mac.

Step 2: Open Finder and click Go > Go to Folder.

Step 3: Type /private/var/db/lockdown/ to open the lockdown folder.

Step 4: Delete all of the files in the Lockdown folder.

Step 5: Start iTunes and connect the iPhone to the mac.

Solution 5: Update Windows to the latest build

Solution 6: Update iOS to the latest build

Step 1: Exit iTunes and disconnect the cable from PC.

Step 2: Put the iPhone on charging and connect it to a Wi-Fi network.

Step 3: Open Settings and tap on the Apple ID.

Step 4: Tap on iCloud > iCloud Backup > Backup Now button and wait for the backup process to complete.

Step 5: Open Settings > General > Software Update. If the iOS update is available, then download and install it.

Solution 7: Update iTunes

If the iTunes is downloaded from the Microsoft Store, go to Microsoft Store and click Downloads and updates to check when it was updated last time.

If the iTunes is downloaded from Apple’s website, open iTunes > Help > Check for Updates.

Solution 8: Allowing all Apple related processes

Step 1: Add the following paths in the exclusion list of antivirus, antimalware and firewall settings:

C:\Program Files (x86)\Common Files\Apple

C:\Program Files\Common Files\Apple

Step 2: Make sure YSloader.exe is not blocked as well.

Solution 9: Temporary disable security applications

Temporarily disable antivirus, firewall and antimalware product.

Solution 10: Add the computer as trusted devices

Step 1: Disconnect the iPhone from the computer and then restart it.

Step 2: Open Settings > General > Reset > Reset Location & Privacy.

Step 3: Connect the iPhone with the computer.

Step 4: When asked for that you trust this computer, tap on Trust.

Solution 11: Repair iTunes

Step 1: Exit iTunes and disconnect the cable from PC.

Step 2: Right-click on the Windows button > Settings > Apps.

Step 3: Click on iTunes > Advanced Options > Repair.

Solution 12: Reset iTunes

Step 1: Exit iTunes and disconnect the cable from PC.

Step 2: Right-click on the Windows button > Settings > Apps.

Step 3: Click on iTunes > Advanced Options > Reset.

Solution 13: Reinstall iTunes

Step 1: Exit iTunes and disconnect the cable from PC.

Step 2: Right-click on the Windows button > Settings > Apps.

Step 3: Click on iTunes > Advanced Options > Uninstall. Follow the on-screen instruction to complete the uninstallation process.

Step 4: Perform the same uninstallation process for the following applications in the order:

• Apple Software Update
• Apple Mobile Device Support
• Bonjour
• Apple Application Support 32-bit
• Apple Application Support 64-bit

Step 5: Restart your PC.

Step 6: Press Windows key + R to open the Run box.

Step 7: Open the following location: %programfiles%

Step 8: Find and delete the following folders (if present):

• iTunes
• Bonjour
• iPod

Step 9: Open the Common folder in the folder of Program Files.

Step 10: Delete the following folders (if present):

• Mobile Device Support
• Apple Application Support
• CoreFP

Step 11: Open the following folder: %ProgramFiles(x86)%

Step 12: Find and delete the following folders (if present):

• iTunes
• Bonjour
• iPod

Step 13: Open the Common folder in the folder of Programs Files (X86).

Step 14: Delete the Apple folder.

Step 15: Delete the following folders in the Common folder (if present):

• Mobile Device Support
• Apple Application Support
• CoreFP

Step 16: Restart your PC.

Step 17: Install iTunes.

Reference

Apple Support > About backups for iPhone, iPad, and iPod touch