I have an Excel file that was created a long time ago, and one of the columns uses a VLOOKUP formula that references a file that does not exist on any computer. Formula:

```
=VLOOKUP(C25,'F:[my_file.xls]abc'!$A$1:$F$65536,2,FALSE)
```

The F: drive does not even exist on my computer. What's confusing is this sequence of occurences:

- Insert a value in cell C25.
- Dialog box comes up asking me to link to F:my_file.xls.
- I hit cancel because file doesn't exist.
- Formula resolves to a correct solution anyway.

So it seems like there's a hidden formula or something that runs like a backup to the VLOOKUP formula? I have Unhid all sheets, columns, and rows, and I found nothing that explains this. Anyone know what's going on? Thanks