I have a 'user' workbook to which users can add notes and highlights.
Each day, they update their 'user' workbook (target) against the
updated data workbook (source). I use a separate 'Comments' sheet to
copy the project numbers and user notes from the 'user' workbook and
also bring in the updated data from the source workbook. There's
basically a vlookup to find the matching project numbers and
copy/paste the user notes comments and the user's highlighting. In
this way, the users are able to maintain their notes and highlighting,
while at the same time bringing in the newly updated project numbers
and information. It does what it's supposed to do, but for some
reason, the copy/paste formats have suddenly become VERY slow.

In a nutshell, I'm trying to copy/paste values and formats of two
separate columns in one sheet to another sheet. I've tried two
separate ways, but no matter what, the pasting of formats takes
FOREVER! The first scenario theoretically should be the fastest
(Copy Destination). And it IS FAST for values, but not formats. The
second scenario of copy/pastespecial yields the same results. Any
thoughts? I appreciate any feedback and suggestions. Thanks.

With wksTarget
LastRowTgt = .Cells(.Rows.Count, "A").End(xlUp).Row
' Copies project numbers in column B to the Comments sheet. Takes
less than 1 second to execute.
.Range("B1:B" & LastRowTgt).Copy
Destination:=wksComments.Cells(1, 1)

' Copies the user notes in column I for the respective project
numbers to the comments sheet. Takes approximately 5 minutes to
execute.
.Range("I1:I" & LastRowTgt).Copy
Destination:=wksComments.Cells(1, 5)
End With

I also tried this:

With wksTarget
LastRowTgt = .Cells(.Rows.Count, "A").End(xlUp).Row
.Range("B1:B" & LastRowTgt).Copy
Destination:=wksComments.Cells(1, 1) 'FAST!
.Range("I1:I" & LastRowTgt).Copy
wksComments.Range("E1").PasteSpecial Paste:=xlPasteValues
'FAST!!
wksComments.Range("E1").PasteSpecial Paste:=xlPasteFormats
'SLOOOOOW!!!
End With

And ultimately, all formatting gets merged on the one wksComments
sheet.

With wksComments
LastRow = .Cells(.Rows.Count, "A").End(xlUp).Row
.Range("G2:G" & LastRow).Formula =
"=IFERROR(VLOOKUP(RC6,R2C1:R56000C5, 2, FALSE)&"""","""")"
.Range("H2:H" & LastRow).Formula =
"=IFERROR(VLOOKUP(RC6,R2C1:R56000C5, 3, FALSE)&"""","""")"
.Range("I2:I" & LastRow).Formula =
"=IFERROR(VLOOKUP(RC6,R2C1:R56000C5, 4, FALSE)&"""","""")"
Columns("I:I").NumberFormat = "m/d/yyyy"
.Range("J2:J" & LastRow).Formula =
"=IFERROR(VLOOKUP(RC6,R2C1:R56000C5, 5, FALSE)&"""","""")"
' Copies the formats for user notes in column E to column J
.Range("E2:E" & LastRow).Copy
.Range("J2:J" & LastRow).PasteSpecial (xlPasteFormats) 'This
is VERY VERY SLOW! About 5 minutes to complete 2200 rows.
End With

Note: there is a project number in every cell for column B (up to
about 2500). There is not a user note for every project note. But,
the cell (actually the row on the Target sheet) may be highlighted.
The same highlighting that is in column B is in column E (because the
whole row on the Target sheet is highlighted). Why would the user
notes column take SO much longer?