R Studio Crashed

[mara]

In that case, you will not be able to read in workspaces made from R 3.6. See my answer, below, with links to relevant changes:

Error listing packages, Error in readRDS(pfile): cannot read workspace version 3 written by R 3.6.0

What version of R are you running? The default serialization format for R changed in May 2018, such that new default format (version 3) for workspaces saved can no longer be read by versions of R older than 3.5 (you can see relevant commits in the CRAN mirror below) R 3.5 was a major update that required new installations of all packages (see post below) All of which is to say that I would recommend updating your version of R.