Upgrading to Catalina

Your MacBook Pro from 2013 can definitely upgrade to macOS Catalina.

When downloading from Apples Servers it is recommended to be connected to your router via cable.

Do not use the mac while it is downloading or any other devices that share the same internet connection.

Open your Applications folder and move Install macOS Catalina.app to the Trash empty the Trash.

Restart your mac and try to download the Catalina installer again.

Before you upgraded to macOS Catalina you should have done the research on how your

third party apps would be affected.

Check third party apps you use have updates available for the new OS.

https://roaringapps.com

Check that your printers/ scanners etc have updated drivers and software available for the new OS.

Catalina does not support 32bit apps.

Your Mac is probably running 32bit apps and these will need to be updated to 64bit apps,

some updates may be free, some may be paid. Use this app to discover which apps you have

are 32bit, https://www.stclairsoft.com/Go64/ then contact the developers of the software to see

if they are offering 64bit updates.

Macs do not need anti-virus protection, there are no viruses that attack the mac.

If you have such software installed get instructions on how to uninstall it from the apps

developers. AV apps and any cleaning or optimisation apps are not necessary, they can

interfere with the macs own built in protection and disk management.

Often these apps will flag up files that you may be encouraged to delete, these files can be

needed system files. All these apps do is working the background using up resources

and slow your mac down.

You should read this article,

Effective defenses against malware and ot… - Apple Community