[R-pkg-devel] Building fails with 'mypackage/DESCRIPTION' does not exist

I have a package which will no longer build after minor changes.  The
problem occurs under both Windows 10 and Linux Mint.  For example, from a
Windows terminal I do:

C:\Users\xyz\OneDrive - ORG\Computing\Devel> R CMD build screenr

and I get:

* checking for file 'mypackage/DESCRIPTION' ... OK
* preparing 'mypackage':
* checking DESCRIPTION meta-information ... OK
* installing the package to process help pages
* saving partial Rd database
 Error in .read_description(ldpath) :
   file 'mypackage/DESCRIPTION' does not exist
 Execution halted

So the first and third lines of output contradict the error message, and of
course mypackage/DESCRIPTION does exist.  I suspect the problem has nothing
to do with the DESCRIPTION file, but have not found way to identify the
actual problem in searches on StackOverflow and elsewhere. My .R files in
mypackage/R contain Roxygen comments, and curiously devtools::document()
adds nothing to mypackage/man.

Any suggestions about how to debug or solve this problem?

Thanks!
Steve

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