I deleted by mistake all log files in WRData folder including its sub-folders (Pkg, Sync, wrUrl). :S
From the nature of log files I don't think it should cause troubles but you never know and hence I rather ask. BTW, WSA including Backup&Sync and Password manager works fine.
How it could happen, easily ... I created a custom rule in CCleaner and forgot to exclude WRData folder. :@
Thanks for your thoughts.