The cause of “bad magic number” error when loading a workspace and how to avoid it?

Question

I tried to load my R workspace and received this error:

Error: bad restore file magic number (file may be corrupted) -- no data loaded
In addition: Warning m         


        

Answer 1

It also occurs when you try to load() an rds object instead of using

object <- readRDS("object.rds")

Answer 2

Also worth noting the following from a document by the R Core Team summarizing changes in versions of R after v3.5.0 (here):

R has new serialization format (version 3) which supports custom serialization of ALTREP framework objects... Serialized data in format 3 cannot be read by versions of R prior to version 3.5.0.

I encountered this issue when I saved a workspace in v3.6.0, and then shared the file with a colleague that was using v3.4.2. I was able to resolve the issue by adding "version=2" to my save function.

Answer 3

Assuming your file is named "myfile.ext"

If the file you're trying to load is not an R-script, for which you would use

source("myfile.ext")

you might try the readRDSfunction and assign it to a variable-name:

my.data <- readRDS("myfile.ext")

Answer 4

The magic number comes from UNIX-type systems where the first few bytes of a file held a marker indicating the file type.

This error indicates you are trying to load a non-valid file type into R. For some reason, R no longer recognizes this file as an R workspace file.

Answer 5

Install the readr package, then use library(readr).

Answer 6

I got that error when I accidentally used load() instead of source() or readRDS().