Using Migration Assistant

Robipapa5 wrote:

Is it safe for me to use Migration assistant when my old iMac is on Catalina and my New iMac is operating onSonoma?

Yes. Migration Assistant is expressly designed for this situation. However because the old iMac uses such an older operating system, it would be best to install fresh all your software; in other words, just transfer over accounts and files, but nothing else. You will need your serial numbers and logins for the old iMac's software in order to get the new versions that run under Sonoma, so be sure to record all those somewhere for use with the new Mac.

Also, be prepared to reinstall printer and scanner drivers, and to reconnect to WiFi access points, etc. You will need to login to your Apple ID as well on the new Mac.

If you follow the steps below to the letter your migration will be smooth and quick.

When you buy a new Mac the easiest, quickest and most reliable method to migrate from the old Mac to the new Mac is to simply connect the old Mac's Time Machine External Hard Disk to the new Mac using a USB cable before you turn on the new Mac. You will likely need a USB A to USB C adapter, you can find them on Amazon for $10 or less. When you start the new Mac for the first time it will startup Setup Assistant (SA), SA will get to a point where it asks if you are migrating from another computer, select Yes  and follow the on-screen prompts and it's done! It is THAT simple.

If you have already done SA on the new computer then simply connect the Time Machine External Hard Disk using a USB cable and launch Migration Assistant (MA) which is located in Applications - Utilities - MA. Then follow the on-screen prompts. 

The ONLY difference between MA and SA is MA will create a new user account that you need to log into.

Both SA and MA migrate applications (not 32 bit apps), data files & settings. They do not migrate Mac OS itself. Some professional apps such as Adobe and Microsoft apps may require re-installing their apps as they will not allow them to be migrated. As long as you kept the security keys for installing their apps, it is not an issue. 

Finally, never EVER use Wi-Fi when doing Setup Assistant or Migration Assistant. Why, it simply fails in most cases. Please read and follow the directions in Setup Assistant and Migration Assistant. If you do not have a Time Machine backup of the older Mac then create one! If you are not aware of Time Machine, please read Back up your Mac with Time Machine and finally if you need an External Hard Disk to use as a Time Machine External Hard Disk then many experience users on these forums prefer the OWC Mercury Elite Pro due to it's reasonable price, high level of quality and ease of use. 

Yes.

Migration moves your Doc's, File's, App's and User Account Settings into the new macOS.

see > Transfer to a new Mac with Migration Assistant - Apple Support

The fastest, easiest and most reliable way to Migrate, is to connect your old Mac's Time Machine backup to the new Mac when prompted during the Initial setup.