this may be the issue with browser permissions that a lot of people have encountered, see this thread for info on how to resolve.
https://ttlc.intuit.com/community/taxes/discussion/re-vanguard-brokerage-update-is-available-from-va...
https://ttlc.intuit.com/community/taxes/discussion/import-tax-document-into-turbotax/00/3775553
