Delete columns if they exist

What you may actually want is to "unpivot" all of your CSVs before merging them.  When you go to create measures, it could be problematic if you have a "wide" data set with specific columns, rather than a "narrow" dataset with a "TimeType" column and the value.  For example:

Emp Name   Online   Meeting   Offline   
Joe        2        1         1

Emp Name   Online    Away    OutofOffice
Mary       3         1       0.5        

"unpivots" (Transform tab, highlight columns, click "Unpivot Columns") to

EmpName  TimeType   Hours
Joe      Online     2
Joe      Meeting    1
Joe      Offline    1

EmpName   TimeType   Hours
Mary      Online     3
Mary      Away       1
Mary      Offline    0.5

which can easily be merged.

Hope this helps,

David

Alternatively: Table.RemoveColumns has a parameter missingField with possible values (and shortcuts 0,1,2):

MissingField.Error (0)

MissingField.Ignore (1)

MissingField.UseNull (2)

It looks like you could use MissingField.Ignore (or its shortcut: 1).