how can i upgrade my mac to mojave.

❗️ Do NOT upgrade until you have made a Time Machine or other backup of your startup drive.

Learn How to Back up your Mac with Time Machine

How to Upgrade  macOS:

The macOS version you can upgrade to depends on the year your Mac was released.

Click the  (Apple) menu at the top of your screen and choose About This Mac.

Check the Compatibility of your Mac with newer versions of macOS:

➡️ macOS 10.14 Mojave is compatible with the Macs listed here

✅ - IF your Mac and apps are compatible, then using Safari only, download the macOS upgrade installer app:

Click > Mojave.

Once downloaded, double-click the “Install macOS [version]” app in the Applications folder to begin the upgrade.

The Age of this computer will Govern what newer version of macOS it will Qualify to install. Use About this Mac from the Apple Icon on Desktop - the required Information will be there.

With the above information in-hand - follow this How to get old versions of macOS and verify what version this computer Qualifies to install.  For Best results use Safari to commence the download as Others may not work.

Safari will open a redirect and open the Apple Store where the download can commence

Make Time Machine Backup  is very useful and can be used to Revert to Previous Working macOS

Notation - Mojave is the Last version to support 32 bit applications / extensions and Drivers. Catalina, Big Sur & Monterey supports only 64 bit and there is no workaround.

Suggest using Go64 to find 32 bit application before attempting the upGrade. Some or many of the Application already installed may required update or upGrades to 64 Bit Versions.

Are there any AntiVirus, Disk Cleaner, Optimizers, Un-installers, etc installed which should be removed as per Developers Instructions. They are useless, unneeded, cause havoc and interfere with the normal operation of the OS and may even Corrupt the OS requiring a Reinstallation

Commencez par ça...

Safe Boot (en maintenant la touche Maj enfoncée au démarrage), le problème se produit-il en mode sans échec ? Peut prendre 10 minutes.

Le mode sans échec tente de réparer les disques, efface de nombreux caches, charge les pilotes sécurisés et empêche le chargement d'extensions tierces. Par conséquent, si le mode sans échec fonctionne, réessayez au démarrage normal.

N'utilisez pas FireFox pour ce lien…

https://itunes.apple.com/us/app/macos-mojave/id1398502828?mt=12

OK, AppStore plante en plein chargement. Et même en redémarrage Cmd ALT R, on se voit proposer la dernière version possible, à savoir dans mon cas Big Sur. Mais quand on a de manière indispensable besoin de Mojave, on fait comment ?