Are you trying to upgrade your Mac from Sierra to High Sierra, the full installer of High Sierra can only be downloaded via the App Store, follow the link here,
In short, any Mac from 2009 or newer has the configuration to support macOS 10.13 High Sierra. This comes to support Apple’s credo that any device made more than 7 years ago is too old and obsolete to support the newer capabilities in software development. As of September 25, 2017, macOS 10.13 High Sierra is publicly available for all Mac users to install. Office 2016 for Mac is fully supported on High Sierra. For the best experience, we recommend you update Office to version 15.38 or later. For updates regarding macOS 10.14 Mojave, see Microsoft Office support for macOS 10.14 Mojave. The macOS High Sierra 10.13.3 Update improves the stability and security of your Mac and is recommended for all users. In keeping with Apple's release cycle, we anticipate macOS 10.13 High Sierra will no longer receive security updates starting in January 2021. As a result, SCS Computing Facilities (SCSCF) is phasing out software support for all computers running macOS 10.13 High Sierra and will end support on January 31, 2021.
https://support.apple.com/en-us/HT208969, scroll down to part 4 where there is a further link that will take you to the App Store where you can download the OS. This will install the latest/ last version of High Sierra 10.13.6
It sounds like you were trying to install an update to High Sierra, possibly the Combo 10.13.6 from the Apple Support Downloads page, you must have an existing copy of High Sierra to do that as that is termed an update. Going from one OS to another, newer OS is called an upgrade and can only be done through the App Store.
Dec 10, 2018 7:02 PM
You're wise to ask, because High Sierra is a big step up from El Cap.
• iCloud
Yes. You don't have to use iCloud at all. Just don't sign in.
Noteworthy composer 2.5 crack.
• Filesystem
Can Mac OS 10.13.3 still read data in OS X Extended format?
Yes
Will Mac OS 10.6.8 be able to read/write data to/from the new Apple File System?
Create Mac Os Recovery Usb
No.. however:
Mac Os 10.13.0
Will upgrading to 10.13.3 change the filesystem or keep the current OS X Extended filesystem?
Macos 10.13 Download
Your Mac's hard disk drive's file system will not be converted. Only Macs incorporating flash storage exclusively will be converted (and you don't have a choice in the matter). Since your Mac still uses conventional magnetic storage media it will remain Mac OS Extended (not APFS). Unless you are morbidly curious do not convert it to APFS on your own.
• Older Applications
I believe so, but I don't spend much time with obsolete apps. Read the following to determine how to definitively answer that question and everything else you should be considering when contemplating an upgrade: Upgrading macOS without fear. That's what I do and that's what I recommend. No risk.
Mar 28, 2018 1:53 PM