stable vba workbook suddenly unstable even older backups are crashing

[IanJG]

I build a complex workbook in 2014 that has a fair amount of vba code, user forms etc in it.
I make regular backups.
About two weeks ago it became unstable in that it will:-

• freeze require task manager to end task
• Error or warning windows pop up but a totally blank
• The workbook will crash excel, but rarely in the same place and does not appear to be code related.
• user windows that are meant to be at the front will be behind their parent form.
• The instability is not limited to one computer.
• The computer that it normally running on sometimes says it does not have enough resources consider 64bit excel
• sometimes says it has run out or insufficient memory to carry out task.

is anybody else having issues?
Has there been an excel update that has changed something?
Any ideas why it would become unstable?
Even when i restore a file from a few months ago when it was working fine that version crashes and plays up.
pull my hair out thanks for ideas, suggestions and help.
kind regards
Ian

 

[mole999]

google search for > microsoft excel service updates history and pick your excel variant

or

Win + i, > Update and Security > View Update History