Error devtools::check - .onLoad failed in loadNamespace() for 'pillar'

Question

Im building an R package and when testing the package using devtools::check() I get an error when the test reaches the installation phase, saying:

    Error: .onLoad failed in loadNamespace() for 'pillar', details:
      call: utils::packageVersion("vctrs")
      error: there is no package called 'vctrs'
    Execution halted
    ERROR: lazy loading failed for package

Neither pillar nor vctrs are mentioned in my description file, so they must be dependents of some other package that I depend on. Both pillar and vctrs are installed and I've also tried reinstalling them. They are stored in the the first .libPath entry. I tried installing pillar from github as was suggested by mfox9 here, but this failed for me, giving this error:

    > devtools::install_github("r-lib/pillar")
    Downloading GitHub repo r-lib/pillar@master
    √  checking for file 'C:\Users\DESCRIPTION' (337ms)
    -  preparing 'pillar': (664ms)
    √  checking DESCRIPTION meta-information ... 
    -  installing the package to process help pages
    -  checking for LF line-endings in source and make files and shell scripts (8.5s)
    -  checking for empty or unneeded directories
    -  building 'pillar_1.4.2.9001.tar.gz'

    Installing package into ‘Z:/’
    (as ‘lib’ is unspecified)
    The filename, directory name, or volume label syntax is incorrect.
    Error: Failed to install 'pillar' from GitHub:
      (converted from warning) installation of package ‘C:/Users/Temp/RtmpgjFfZl/file32586b634e28/pillar_1.4.2.9001.tar.gz’ had non-zero exit status

(note: z:/ is my correct R library address)

Can someone please help?

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> sessionInfo()
R version 3.6.1 (2019-07-05)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 10 x64 (build 15063)

Matrix products: default

locale:
[1] LC_COLLATE=English_United Kingdom.1252  LC_CTYPE=English_United Kingdom.1252   
[3] LC_MONETARY=English_United Kingdom.1252 LC_NUMERIC=C                           
[5] LC_TIME=English_United Kingdom.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] pillar_1.4.2

loaded via a namespace (and not attached):
 [1] Rcpp_1.0.2        rstudioapi_0.10   magrittr_1.5      usethis_1.5.1    
 [5] devtools_2.2.0    pkgload_1.0.2     R6_2.4.0          rlang_0.4.0      
 [9] tools_3.6.1       pkgbuild_1.0.5    DT_0.8            packrat_0.5.0    
[13] sessioninfo_1.1.1 cli_1.1.0         withr_2.1.2       remotes_2.1.0    
[17] htmltools_0.3.6   ellipsis_0.2.0.1  assertthat_0.2.1  digest_0.6.20    
[21] rprojroot_1.3-2   crayon_1.3.4      processx_3.4.1    callr_3.3.1      
[25] fs_1.3.1          htmlwidgets_1.3   ps_1.3.0          curl_4.0         
[29] testthat_2.2.1    glue_1.3.1        memoise_1.1.0     compiler_3.6.1   
[33] desc_1.2.0        backports_1.1.4   prettyunits_1.0.2

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