Why am I getting Run time error 1004 using Vlookup?

Question

I have a macro where I go through each row of Newest_closed worksheet and: - get the NCASTS string in column A - look for the string in Newest_opened worksheet using Vlookup - if found, get contents of Column K and call it "Resp_Unit2" - paste value of "Resp_Unit2" in Column K of Newest_closed worksheet NOTE: Newest_opened and Newest_closed are Public-dimensioned strings, and actual names of the worksheets are created in another Sub.

When I reach the line of code that uses Vlookup, I get "Run-time error 1004: Application-defined or object-defined error". Why am I getting this error?

I have used "Immediate" window to query values of Last_row_1, Last_column_1, and NCASTS (for loop counter x = 2). All queries return valid values.

I have also used "Immediate" window to execute:

Worksheets(Newest_opened).Range(Cells(1, 1), Cells(Last_row_1, Last_column_1)).Select

Excel shows the correct range of cells selected in the worksheet.

    Sub Assign_Resp_Unit_2()
    'This sub does the following:
    '
    '   - for each NCASTS in the Newest_closed worksheet:
    '       - searches in the Newest_opened worksheet for that NCASTS
    '       - if NCASTS found, gets the value from the "Responsible Unit"    column and pastes it in the same column in the Newest_closed worksheet
    '
    Dim x As Integer
    Dim NCASTS As String
    Dim Resp_Unit2 As String
    Dim Last_row_1 As Long
    Dim Last_column_1 As Long
    Dim New_opened_rng As Range
   '
   'Find range of Newest_opened worksheet
   Worksheets(Newest_opened).Activate
   Last_row_1 = Cells(Rows.Count, 1).End  (xlUp).Row                           'get number of last row in table
   Last_column_1 = Cells(1, Columns.Count).End(xlToLeft).Column              'get number of last column in table
   '
   'Set the variable "Newest_opened_range" to be the Range of the Newest_opened worksheet
   Set New_opened_rng = Worksheets(Newest_opened).Range(Cells(1, 1), Cells(Last_row_1, Last_column_1))
   '
   'search Newest_opened worksheet for Responsible Unit
   '
   'Loop through each cell in Column A of Newest_closed until a blank cell is encountered (i.e. end of entries)
   '
   Worksheets(Newest_closed).Activate
   x = 2   'initialize row counter
   Do Until IsEmpty(Cells(x, 1))
       '
       'Get NCASTS number from Column A of Newest_closed worksheet
       NCASTS = Cells(x, 1)
       '
       'Search for NCASTS number in Newest_opened worksheet and find  corresponding Responsible Unit entry;
       'Preset string variable Resp_Unit2 to "Not found" for case where NCASTS number is not in the range
       '
       Resp_Unit2 = "Not found"
       On Error Resume Next
       Resp_Unit2 = Application.WorksheetFunction.VLookup(NCASTS, New_opened_rng, 11, False)
       '
       'Paste value of Resp_Unit2 to Responsible Unit column (column L) for same NCASTS in Newest_closed worksheet
       '
       Sheets(Newest_closed).Cells(x, 12).Value = Resp_Unit2
       '
       'Move to next row of Newest_closed worksheet
       '
       x = x + 1
   '
   Loop
   '
   End Sub

Answer 1

Rather than vlookup , since you're working in a specific column out in yonder (and hoenstly ensuring it's the 11th column of the range is its own PITA (subjective, I know)), you might try index / match to ensure you're only having to specify your lookup and output ranges. Will make a couple changes, like ensuring to qualify ALL ranges (even the cells inside of range ) :

Dim OutputRng as Range, SearchRng as Range, NCASTS as String, Resp_Unit2 as String, Last_row_1 as Long
With Worksheets(Newest_opened)
    Set SearchRng = .Range(.Cells(1,1),.Cells(Last_row_1,1)) 'Assumes Column A is searched
    Set OutputRng = .Range(.Cells(1,11),.Cells(Last_row_1,11)) 'Assumes Column K has otuput
    Last_row_1 = .Cells(.Rows.Count, 1).End(xlUp).Row  'qualified
    Do Until IsEmpty(.Cells(x, 1)) 'qualified this, but may want to try a for or for each loop?
        NCASTS = .Cells(x, 1).Value 'qualify it, don't use .activate and added .value
        Resp_Unit2 = Application.Index(OutputRng, Application.Match(NCASTS, SearchRng, 0))
        x = x+1
    Loop
End With

Related to your error, you might not have an exact match, which would throw an error; using WorkSheetFunction you will get an error that flags, similar to the worksheet's #VALUE . FoxFire touches on that in the comments section of the post which is quite important.