False positives and False Negatives with Instr function - arrays

Question

I am trying to look through an array for values using InStr. However, I am getting false positives and false negatives.
I.e. there will be a string match and no match will be reported or no match reported even though the string matches exactly.
It requires Outlook. It converts the highlighted emails into a text file placed in the specified path. It then searches the text file for the delimeter by reading the text into an array and searching the array contents. However, as mentioned, even when the substring is in the array, InStr returns false positives and false negatives. I have tried binary and textual comparison methods and various comparison strings.
Any ideas?
Notes: 1)after becoming frustrated with InStr, I attempted to use an if then statement to compare the array to the delimeter string, which is what is shown in the last lines of my code.
2)i have set the delimeter as "xxxxx" which you can see in the lines following the set of objfile.write commands.
3)I have tried to use both text and binary comparison modes with the instr function
3) Ultimate goal:
a)Extract highlighted emails from outlook and combine into one text file.
b)Sort the delimited text file based on the text of the email (if text between delimiters contains y, put into array y, if x...etc.)
c)print arrays into email in my specified order (e.g. x, y, z)
this is because the emails arrive at different times each day, but must be organized into the same order each day for the final summary email.
Thanks.
Below is my code:
Sub MergeTextFromSelectedEmailsIntoTextFile()
Dim objFS As New Scripting.FileSystemObject, objFile As Scripting.TextStream
Dim objItem As Object, strFile As String
Dim wrapArray() As String
If ActiveExplorer.Selection.Count = 0 Then Exit Sub
strFile = InputBox("Please enter the full path and file name for the merged text:" _
, "Enter File Name")
Set objFile = objFS.CreateTextFile(strFile, False)
If objFile Is Nothing Then
MsgBox "Error creating file '" & strFile & "'.", vbOKOnly + vbExclamation _
, "Invalid File"
Exit Sub
End If
For Each objItem In ActiveExplorer.Selection
objFile.Write vbCr
objFile.Write (vbCr & Chr(10) & Chr(13) & ("xxxxx") & Chr(13) & Chr(13) & vbCr & vbLf)
objFile.Write (vbCr & vbLf & objItem.Body)
objFile.Write (vbCr & vbLf & Chr(13))
Next
objFile.Close
'Define variables for writing to array
Dim i As Integer
Set objFile = objFS.OpenTextFile(strFile, ForReading)
'write file contents to array
Do Until objFile.AtEndOfStream
ReDim Preserve wrapArray(i)
wrapArray(i) = objFile.ReadLine
i = i + 1
Loop
Dim xxxxx As String
xxxxx = xxxxx
'check each array index for contents
'note i have tried
''if instr(0, wraparray(i), "xxxxx",0) then msgBox "FoundDelim at line " & i
For i = LBound(wrapArray()) To UBound(wrapArray())
If wrapArray(i) = "xxxxx" Then MsgBox "FoundDelim! at line " & i
Next i

Answer 1

Note that InStr returns an integer, so testing the result of the function as a boolean should result in inconsistent behavior. Try this:
If InStr(wrapArray(i),"xxxxx") > 0 Then
MsgBox "FoundDelim! at line " & i
End If