this is the code to properly reference sheets:
Option Explicit
Sub InvestorReport()
Dim investorname As String
Dim finalrow As Long
Dim i As Long 'row counter
With Sheets("Sheet001") '<--| refer to "Sheet1" sheet
.Range("D6:K50").ClearContents '<--| with every initial "dot" you keep referencing the object after the "With" keyword ("Sheet1" sheet, in this case)
investorname = .Range("B3").value
End With
With Sheets("Investments") '<--| refer to "Investments" sheet
finalrow = .Cells(.Rows.Count, "I").End(xlUp).row '<--| .Cells and .Rows refer to "Investments" sheet
For i = 2 To finalrow
If .Cells(i, 1) = investorname Then
.Range(.Cells(i, 2), .Cells(i, 12)).Copy '<--| .Range and .Cells refer to "Investments" sheet
Sheets("Sheet001").Range("D100").End(xlUp).Offset(1, 0).PasteSpecial '<--| here all references are explicitly made to "Sheet1" sheet
End If
Next i
End With
Sheets("Sheet001").Range("B3").Select
End Sub
and here follows the code to avoid loops and exploiting Autofilter:
Sub InvestorReport2()
Dim investorname As String
Dim finalrow As Long
Dim i As Long 'row counter
With Sheets("Sheet001") '<--| refer to "Sheet1" sheet
.Range("D6:K50").ClearContents '<--| with every initial "dot" you keep referencing the object after the "With" keyword ("Sheet1" sheet, in this case)
investorname = .Range("B3").value
End With
With Sheets("Investments") '<--| refer to "Investments" sheet
With .Range("A1", .Cells(.Rows.Count, "L").End(xlUp)) '<--| refer to "Investments" sheet columns A to I fom row 1 (header) down to last non empty one in column I
.AutoFilter field:=1, Criteria1:=investorname '<--| filter data on first column values matching "investorname"
If Application.WorksheetFunction.Subtotal(103, .Cells.Resize(, 1)) > 1 Then '<--| if any cell has been filtered...
.Offset(1, 1).Resize(.Rows.Count - 1, .Columns.Count - 1).SpecialCells(xlCellTypeVisible).Copy '<--| ... copy filtered cells skipping headers and first column...
Sheets("Sheet001").Range("D100").End(xlUp).Offset(1, 0).PasteSpecial '<--| ...and paste them
End If
End With
.AutoFilterMode = False '<--| .. show all rows back...
End With
Sheets("Sheet001").Range("B3").Select
End Sub