File Collisions

A file collision occurs when it is unclear whether the source or the destination file should be replaced.

Three sorts of file collision can occur:  one-way;  two-way;  and date.

A one-way collision can occur when the Also Synchronize in Reverse checkbox is unchecked.  In this case a collision will be flagged if the destination file was modified more recently than the source file.

A two-way collision can occur when the Also Synchronize in Reverse checkbox is checked.  In this case a collision will be flagged if both the source and destination files have been modified since the last synchronization.  Note that if both source and destination files have the same modification date, a collision will not occur, because no file will be overwriting another.

A date collision occurs if any file has been modified after the current system time.

A file / folder collision occurs when an attempt is made to replace a file with a folder of the same name, or a folder with a file of the same name.  SwitchBack will flag this collision, allowing you to cancel the proposed synchronization.  If the synchronization proceeds an error will be generated for the file / folder pair, which will remain unchanged.

When a collision occurs, the report window will automatically appear, detailing all the collisions and the proposed synchronization.  A checkbox at the bottom of the report window is labelled “Show Collisions Only”.  It allows you to toggle between showing the entire report or just those files causing a collision.  When checked you can quickly see which files are causing the collision, rather than having to scroll through the entire report.  

Unless specifically instructed otherwise, SwitchBack will always replace an older file with a newer file, and you may therefore choose to either continue or cancel the proposed synchronization.  See the next section (Ignoring File Collisions) for a way to allow SwitchBack to replace a newer destination file with an older source file.

Please read the Network Time Discrepancies section for important information regarding the way SwitchBack handles network time discrepancies.

Ignoring File Collisions

You can force SwitchBack to ignore some of these collisions.  Checking the Allow Collisions to be Ignored checkbox adds a Collision item to the Special menu.  Choosing this Collision item brings up a dialog box with the following checkboxes:

Destination File Newer than Source File

  ource Always Overwrites Destination

Both Files Modified Since Last Synchronization

Any File Newer than Current System Time

These items are all unchecked by default, indicating that SwitchBack will report on these collisions.  You may check one or more of these items if you don’t wish to be warned of that type of collision.

An example might be performing a one-way backup where the backed up file may have been modified.  In this situation you also have the option of checking the Source Always Overwrites Destination checkbox.  This allows SwitchBack to replace the newer destination file with the older source file.

It is recommended that you leave all these items unchecked, unless you are absolutely sure you want one or more of these checks to be ignored.