12.6 on Windows fails to install

With that particular error try repairing Apple Software Update from the programs & features control panel, and then try to update iTunes again.

For general advice see Troubleshooting issues with iTunes for Windows updates.

The steps in the second box are a guide to removing everything related to iTunes and then rebuilding it which is often a good starting point unless the symptoms indicate a more specific approach. When reinstalling right click on the downloaded setup file and use run as administrator.

Review the other boxes and the list of support documents further down the page in case one of them applies.

The further information area has direct links to the current and recent builds in case you have problems downloading, or want to revert to an older version if the current one won't work properly for you at the moment.

Your library and device backups should be unaffected by these steps but there are links to backup and recovery advice should it be needed.

tt2

If you have difficulty downloading the current iTunes installer file try; unticking the "Keep me up to date..." box, clearing your browser's cache, changing pop-up blocker settings, right-clicking or ctrl-clicking the download button, using an alternate browser, using the direct links from here, or download the installer on another computer and transfer to yours with a USB drive. Another user also mentioned pausing and resuming the download to help it complete as a possible workaround for network timeout issues. It may also help to temporarily disable AV software.

Once you've downloaded the setup file right-click on it and use the Run as administrator option.

See Troubleshooting issues with iTunes for Windows updates if you have any further trouble with the installation.

tt2

I take it back. 12.6 is looking like a lemon after all. It would seem that among other issues (bugs with Get Info and multiple albums, and reset plays MIA again!) Tunes 12.6.0.100 has problems accessing the iTunes Store for some users, which can make it freeze on launch. See the iTunes installers section of Troubleshooting issues with iTunes for Windows updates for links to the 12.5.5.5 build and roll back advice.

tt2

Given what appears to be numerous users having this issue with iTunes 12.6, isn't it safer to just wait for Apple to fix what appears to a widespread issue? (I'm having the same troubles but honestly don't want to go through all these steps and put my library at risk if I don't have to -- caveat: I did try the first step - repairing Apple Software Update and still not working)

Thank you

The reality is that most users are able to upgrade uneventfully. People generally come to this site when things go wrong. Apple cannot fix your broken install remotely, particularly since they have no reason to know it is bust, nor is there any guarantee that the next installer would workaround whatever problems have caused it to fail for you this time. The software tear down and rebuild I've suggested leaves your library intact, but you do already keep a backup don't you? It is essentially the same process that Apple advise themselves. but with additional information gathered while helping others troubleshoot their upgrade issues.

tt2

I think your reality may be self constructed. It appears that Apple issued a lame update package that fails in many cases, including for users (like me) that should have had no reason to question the state of their update services. We shouldn't have to do a laborious work around due to Apple's fail. I think you will find that many more users will reexhibit this issue set as the days go by. They should reissue the package

Of course I have no official figures to work with, only observations of activity on this site. There have actually been two releases of 12.6, 12.6.0.95 and 12.6.0.100 released two days apart. I've no idea what was patched from one to the other, but it is unlikely to address an installation issue. The last builds that I noticed showing significantly larger numbers of failed installs than usual were 12.1 and 11.1.4, otherwise there are always more reports just after a new release, and a steady background level in between them.

tt2

Quite a waste of time trying to install 12.6. Going through the MS suggestions made no difference. Finally, going back and restoring 12.4.1.6 made the difference. I assume that since the earlier package installed but the latter did not means that MS is off the hook and the problem lies in the 12.6 install package. Let us know when there is a reliable 12.6 package.

I get to 88.5megs every time and it stops and give an Apple error with no information. Thanks again Apple for another messed up update. There is a pattern and common denominator here.