cannot install itunes on win 8.1

With that particular error try repairing Apple Software Update from the programs and features control panel then try again. This appears to be caused by the old copy of ASU failing to uninstall when asked to by the new version's setup script. And yes, it would be nice if there were meaningful errors, and even better if the installer could issue the appropriate resolution all by itself, however things are never that easy.

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

I am also having issues reinstalling iTunes for Windows 8.1after it didn't recognize my new iPhone SE, and reinstalling it was suggested. As with the original poster, I am beyond redemption with Apple and will no longer purchase any more Apple products and will completely phase them out after my current devices become obsolete.

The installer gives the oh so helpful message of: "Errors occurred during installation....." and it simply tells me: "To complete the installation run the installer again". It's great to see that Apple has such respect for its customers that it thinks putting us in an endless loop is acceptable.

The Temp log file (SetupAdminE28.log) has this helpful tidbit:

=== Logging started: 6/9/2017 9:50:50 ===

Command Line: /evt E658 /pid 6496 /mon 580 592

Duplicating handle 580 from 0x00000068 failed. GetLastError() = 5l

Duplicating handle 592 from 0x00000068 failed. GetLastError() = 5l

Exiting with code: 1

I have my own work to get done, and I don't appreciate being put in a position to provide free troubleshooting assistance to Apple's developers, especially since that consideration isn't returned by providing a real error message with advice that will actually work.

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. 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, need to revert to an older version or want to try the iTunes for Windows (64-bit - for older video cards) release as a workaround for installation or performance issues, or compatibility with QuickTime or third party software.

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

There is a mild hint from another thread that disabling Windows Firewall during the reinstall might help with the Microsoft.VC80.CRT error. I'd also try the "for older video cards" version if you haven't already done so.

tt2