Needs macros to delete row ranges in excel

try this on a copy.

Sub test()
With ActiveSheet
    .AutoFilterMode = False
    With Range("W2", Range("W" & Rows.Count).End(xlUp))
        .AutoFilter 1, "*Linux; Android 6.0.1;*"
        On Error Resume Next
        .Offset(1).SpecialCells(12).EntireRow.Delete
    End With
    .AutoFilterMode = False
End With
End Sub

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Won't this one delete the top row (the header) which contains the text "USER_AGENT" but not "*Linux; Android 6.0.1;*"?

Sub test()
With ActiveSheet
    .AutoFilterMode = False
    With Range("W2", Range("W" & Rows.Count).End(xlUp))
        .AutoFilter 1, "*Linux; Android 6.0.1;*"
        On Error Resume Next
        .Offset(1).SpecialCells(12).EntireRow.Delete
    End With
    .AutoFilterMode = False
End With
End Sub

Please try this....(Before trying this, create a backup of your data)

Sub DeleteRows()
Dim lr As Long
Application.ScreenUpdating = False
lr = ActiveSheet.UsedRange.Rows.Count
With Range("W1:W" & lr)
   .AutoFilter field:=1, Criteria1:="<>*Linux; Android 6.0.1;*"
   If Range("W2:W" & lr).SpecialCells(xlCellTypeVisible).Cells.Count > 1 Then
      Range("W2:W" & lr).SpecialCells(xlCellTypeVisible).EntireRow.Delete
   End If
   .AutoFilter
End With
Application.ScreenUpdating = True
End Sub

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@Professor
Sorry, didn't refresh the page before posting. My sincere apologies.

@Neeraj,
you do not need to apologise, we are friends , at the end of the day what matter is, that user gets the help.  
It happens to me too :-)

Thanks Professor, so nice of you. :)

thanks my friend :)

It seems like I was not specific enough. My apologies.

I want to delete rows that are missing these two strings in Col W.

USER_AGENT and Linux; Android 6.0.1;

"...  that are missing a string in a certain column."

It seems the solutions thus far delete the rows that contain  Linux; Android 6.0.1;

I want the "NOT" of that operation

Did you try the code I suggested in Post ID: 41761228?
I think that does what you are trying to achieve.

This is what I see when I run 41761228

ID: 41761229 actually deleted every line that contained "*Linux; Android 6.0.1;*"in column W.

I didn't mention at first that I am running on a MAC book because I did not think it significant: would these functions run differently on a PC vs MAC?

Well that shouldn't be the case.
The code is assuming that row1 is the header row and the actual data starts from row2.
Can you upload a small sample workbook to work with (max 50 rows) and highlight the cells in col. W that need to be deleted?

How about if I just extract column W? What is in that column is fairly generic and not proprietary---but most of the 52 columns are proprietary and I would need to obfuscate them.

That's completely fine.
Just show what's there in col. W and highlight the cells which needs to be deleted.

This took a while: this is a sheet with 30,000 + rows and 55 columns and I wonder if the size made a difference.

The rows to be deleted are in purple.

49      Mozilla/5.0 (Linux; Android 6.0.1; D6503 Build/23.5.A.1.291; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/52.0.2743.98 Mobile Safari/537.36

this is the portion of the string I care about: "Linux; Android 6.0.1; "

If you can't duplicate this issue with this smaller spread sheet, I may need to upload a larger one.
test.xlsx

Hmmmmm.

This works on my PC but not my Mac Book.

There must some functional difference between Excel on MAC and Excel on my PC.

I'll need to retest all the suggestions on my PC tonight

I am not sure why, but your solution works perfectly on Excel running on my PC but does not work when running Excel on my Mac Book.

Can you try the following code to see if that works on your Mac also?

Sub DeleteRows()
Dim lr As Long
Application.ScreenUpdating = False
lr = ActiveSheet.UsedRange.Rows.Count
With Range("W1:W" & lr)
   .AutoFilter field:=1, Criteria1:="<>*Linux; Android 6.0.1;*"
   If Range("W1:W" & lr).SpecialCells(xlCellTypeVisible).Cells.Count > 1 Then
      Range("W2:W" & lr).SpecialCells(xlCellTypeVisible).EntireRow.Delete
   End If
   ActiveSheet.ShowAllData
End With
Application.ScreenUpdating = True
End Sub

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It did work on the MAC. What did you change?

Glad to know that.
I replaced line#10 .AutoFilter with ActiveSheet.ShowAllData.

Thanks! Great work!

Thanks experts!