Configuring a profile to use the correct drive letter when the drive letter is (or may later be) unknown

We have a simple tutorial that explains how to use a drives unique serial number instead of the drive letter.

In some situations it is not known at profile creation time what drive letter Windows will assign to an external drive, for example, when it is plugged in. To get around this the variables SERIAL or LABEL can be used. For example, if your external drive has a serial number of ABCD-EFGH then you could set your source or destination to:


As an alternative the label variable can be used when the drive label is known, e.g.

%LABEL=My Drive%\backup\

When the profile is run SyncBack will substitute the variable with the drive letter of the drive with that serial or label, e.g.


An easy way to get the serial number, or label, or a drive is to click on the down arrow to the left of source/destination paths on the Simple settings page when modifying a profile. As an alternative, to get the serial number of a drive you could go to the command prompt and type dir x: (use the appropriate drive letter). The serial number of the drive is displayed in the header of the output. Note that the SyncBackSE/Pro log file also includes the serial number of the source and destination.

Note that these variables are not available in SyncBackFree.

The following article explains how to assign permanent drive letters to external devices: