Internal Sync Options

<rowentry>
    <name>skipdownloadsforadvancedchecks</name>
    <type>string</type>
    <value>1</value>
</rowentry>

By default, when checkcrc and checkmodtime is enabled, resetting sync data will redownload all files from the server irrespective whether the file already exists locally.

Adding this flag will skip files that already exist locally. The possible issue is that you might have locally modified files that will not again upload to the server after the initial sync (because sync assumes this is the local state)