Do you need to work offline?
The Add-In RefWorks feature for versions of Word 2016 and above maintains a live connection to RefWorks and does not allow offline work.
Use the Write-N-Cite plug in (download from the Tools in RefWorks) for newer versions of Word instead of the Add In if you are planning to work offline. You will need to choose to work with one or the other (do not install both). This option is not available for those using Word for Mac.