I have a brand new IMAC with 16 gigs of RAM all of which is sitting there completely available. I loaded the trial version of Adobe Elements 2021. It can open PDF files as large as 135 MB no problem. I have several PDF files that are larger.....235 MB and 350 MB. When I try to open them with Adobe Elements I get an error message that says: Could not complete the open command because there is not enough memory (RAM). When I go to the Adobe Elements ...Preferences....Performance dialogue.....it says that I have over 14 gigs of available memory. The dialogue box lets you allocate varying amounts of memory to Adobe elements. I have tried adjusting the allocated amount for the Adobe Elements to use...in varying amounts from 10 more gigs to all the available 14.2 gigs. Same problem occurs. When I try to open a file with 235 MB it says that there is not enough memory. This is a brand new IMAC. Any insights.
Please check in Activity Monitor (Applications/Utilities). (At the top, set the Show menu to All Processes.) Click the Real Memory column header so that the point of the triangle is down. This will bring the processes using the most RAM to the top. If there's one using a lot (500MB or more), quit it if you don't need to have it open.
If there isn't anything using a lot of RAM, the easiest way to fix it would probably be to uninstall and reinstall Elements.
By the way the RAM can't be all sitting there available. That's not possible. The system will be using some, other apps (including invisible apps) will be using some. Still, 16GB should be plenty. The age of the iMac is not a factor, RAM doesn't fill up because a system is old.