sierra security update 2019-004 application memory

When rebooting the computer uncheck the "Reopen apps" from the shutdown dialog.

Try booting into Safe Mode to see if the same problem exists. It loads minimal drivers, disables Startup & Login items, deletes some temp & cache files as well as running a file system check. The display may flash or flicker due to the very basic video drivers used in Safe Mode. If Safe Mode works, then try rebooting normally.

If you still have problems, then run EtreCheck and post the report here using the "Additional Text" icon which looks like a piece of paper.

I get a message that it has run out of application memory.

There are 2 reasons for getting this message:

1. Your boot disk has run out of storage and can no longer create page/swap files to off-load memory. While not impossible, this is generally the lest likely reason.
2. You have an application (or several applications) that are asking for so much virtual memory that the kernel cannot create any more page table entries to map the virtual addresses. Effectively the kernel has reached a point where it would use up most of memory with virtual memory page tables and there would be nothing left for the applications to use. This is the more common cause, and it is generally because an application has lost track of the fact that it keeps asking the operating system for more virtual memory, uses and then does not give the virtual memory address space back.

Unless you know your boot disk is full, then in an Applications -> Utilities -> Terminal session issue the following command

ps axo vsz,comm | sort -n

This will show the virtual memory (in kilobytes) for every process sorted with the worst offenders last.

This is only useful if the offending programs are still running. For example when you start to notice that your system is getting slow and your apps start to have issues.

Also try booting into another admin account to see if the same thing happens.