I've developed a large workbook with a macro that creates multiple copies of
three template sheets and fills them in using data from various other hidden
sheets, then extracts 15 datasheets from a source pivot table, then moves all
these new sheets into a new workbook, which is then saved as a report,
leaving the original workbook in its original state.

The macro was working, with a few possible bugs, but now it's suffering
complete failure. It successfully moves most of the sheets but then after
moving seven of the datasheets, the macro fails (no chance to debug) halfway
through moving the data sheets.

Bizarrely, I then cannot manually move them (no error, Excel just does
nothing with it) so I'm sure it's not a coding error. I could still copy the
sheet, so I changed the macro to do this and delete the original, but it
still fails, oddly enough at the same place.

Any ideas why this is happening? Or even any clues as to what I should be
looking for? I'm quite new to VB so I may have missed something fundamental
in the way I've set this up. For example, I'm setting WB publicly as the
active workbook at the beginning of the macro, and referring to it
throughout, but I've no idea if I should be doing this as I'm effectively
increasing the memory requirements of WB as I go along. This is certainly my
first instinctive thought on it.