Apple - How do I get old apps like Photoshop CS5 to work on macOS Mojave

The first thing I would try is changing the security and privacy settings in System Preferences. You can do this as follows:

1. Go to Apple > System Preferences…
2. Click on Security & Privacy
3. Select the Privacy tab at top right
4. In the lefthand pane select the Accessibility option
5. At bottom left of the window make sure the padlock is unlocked (if not, select it and enter your password)
6. In the list of apps on the right-hand side, make sure Photoshop and any of the other apps you’re having problems with are ticked
7. OPTIONAL: If any apps you’re having problems with are not listed, click on the + button under the list and navigate to the apps to select and add them to your list. Once done, then repeat Step 6
8. Make sure you lock the padlock again that you unlocked at Step 5
9. Quit and restart any apps you’ve just allowed to control your Mac (i.e. if they were already open)

Now try running Photoshop etc again to see if they work.

Our go-to for preserving valuable but obsolete software is to put it inside a virtual machine using Oracle Virtualbox or VMWare, that way you can use it on any system forever without worrying about it being broken by OS upgrades / hardware failure etc.

Finally a solution is on the horizon...

I went through a crazy voyage with my CS5 Creative Suite PS Version, You have to consider serveral things that could be an issue

-> update to 12.0.4 or even 12.0.5 here you find a way to run "old" incompatible updater... be sure to run them with sudo https://forums.adobe.com/thread/2552114

-> Font Setting in PS, set preview to small, if this isn´t set, PS will crash on using font tool, by rendering the font preview box

-> This https://www.macworld.co.uk/how-to/mac-software/open-apps-wont-work-mojave-photoshop-3684425/ was my second issue... and i ran into another version of it, from one day to the other, PS crashed when i tried to use for e.g. tools or move the image. I tried a lot of stuff. But i forgot to maybe consider to reimplement the security thing mentioned in linked article...

-> Another issue could be messed up fonts, use FontBook to scan your fonts, remove all which are marked RED

-> Sometimes Old Plugins could also crash PS... try to disable them with the Adobe Extension Manager, depending on your installation, you have to maybe run the Manager wih root, terminal: sudo (drag here the .dmg -> show package content -> Contents -> MacOS -> AdobePatchInstaller to insert the path in the terminal)

The only thing i could´nt get rid of is the crash message when i close PS

So i hope this helps