Preview version of R Studio 1.2.1326 in Windows cannot install (error opening Qt dll libraries)

I'm trying to install the daily preview version of R Studio (1.2.1326) on a Windows 10 machine. Download seems OK, but when I try to execute the installer, during setup it throws a series of error messages:

Error opening file for writing:
C:\Program Files\RStudio\bin\Qt5Core.dll

with an Abort/Retry/Ignore option.

Retry fails. Ignore leads to additional errors opening

Qt5Gui.dll
Qt5Network.dll
Qt5Positioning.dll

etc.

Any ideas?