Unable to delete sheets that meet a condition - excel

Question

I keep getting
runtime error 1004 - Application defined or object defined error
for the code below. Could you help me figure out why this is happening?
Option Explicit
Sub DeleteSheet()
Dim Sh As Worksheet
Application.DisplayAlerts = False
For Each Sh In ThisWorkbook.Worksheets
If Application.WorksheetFunction.Search("Generation", Sh.Range("A1").Value, 1) = 1 Then
Sh.Delete
End If
Next Sh
Application.DisplayAlerts = True
End Sub

Answer 1

You can't delete a sheet which is also a control variable in a loop. Use a counter instead to iterate through the sheets, then delete using the counter, eg
dim sheetCount
dim i
sheetCount = ThisWorkbook.Worksheets.Count
for i = sheetCount to 1 step -1
dim sh as Worksheet
set sh = ThisWorkbook.Worksheets(i)
If Application.WorksheetFunction.Search("Generation", sh.Range("A1").Value, 1) = 1 Then
ThisWorkbook.Worksheets(i).Delete
End If
next i

Answer 2

Delete Worksheets Using an Array of Worksheet Names
I couldn't reproduce the exact error.
The covered scenarios producing errors were the following:
when generation was not found in cell A1,
the last sheet cannot be deleted,
when a sheet was very hidden.
VBA has its own FIND or SEARCH equivalent called Instr.
In the workbook containing this code (ThisWorkbook), it will delete all worksheets whose cell A1 contains a string starting with Generation.
Option Explicit
Sub DeleteSheets()
Dim wsCount As Long: wsCount = ThisWorkbook.Worksheets.Count
Dim wsNames() As String: ReDim wsNames(1 To wsCount) ' Worksheet Names Array
Dim ws As Worksheet
Dim n As Long
For Each ws In ThisWorkbook.Worksheets
' Check if 'A1' contains a string starting with 'Generation'.
If InStr(1, CStr(ws.Range("A1").Value), "Generation", _
vbTextCompare) = 1 Then
n = n + 1 ' next array element
wsNames(n) = ws.Name ' write the worksheet name to the array
End If
Next ws
' Check if no worksheet name was added to the array.
If n = 0 Then Exit Sub
' Resize the array to the number of found worksheets.
If n < wsCount Then ReDim Preserve wsNames(1 To n)
' Delete the worksheets, without confirmation, in one go.
Application.DisplayAlerts = False
ThisWorkbook.Worksheets(wsNames).Delete
Application.DisplayAlerts = True
End Sub