When closing R Studio at the end of a R session, I am asked via a dialog box: "Save workspace image to [working directory] ?"
What does that mean? If I choose to save the workspace image, where is it saved? I always choose not to save the workspace image, are there any disadvantages to save it?
I looked at stackoverflow but did not find posts explaining what does the question mean? I only find a question about how to disable the prompt (with no simple answers...): How to disable "Save workspace image?" prompt in R?
What does that mean?
It means that R saves a list of objects in your global environment (i.e. where your normal work happens) into a file. When R next loads, this list is by default restored (at least partially — there are cases where it won’t work).
A consequence is that restarting R does not give you a clean slate. Instead, your workspace is cluttered with existing stuff, which is generally not what you want. People then resort to all kinds of hacks to try to clean their workspace. But none of these hacks are reliable, and none are necessary if you simply don’t save/restore your workspace.
If I choose to save the workspace image, where is it saved?
R creates a (hidden) file called .RData in your current working directory.
I always choose not to save the workspace image, are there any disadvantages to save it?
The advantage is that, under some circumstances, you avoid recomputing results when you continue your work later. However, there are other, better ways of achieving this. On the flip side, starting R without a clean slate has many disadvantages: Any new analysis you now start won’t be in a clean room, and it won’t be reproducible when executed again.
So you are doing the right thing by not saving the workspace! It’s one of the rules of creating reproducible R code. For more information, I recommend Jenny Bryan’s article on using R with a Project-oriented workflow
But having to manually reject saving the workspace every time is annoying and error-prone. You can disable the dialog box in the RStudio options.