Vlookup only works after I use "Find"

[Cypdog]

I have a fairly simple vlookup that looks up check numbers from another worksheet and returns a value in that array. I have performed this for every month of the year except one and the formula works in all of the other spreadsheets. When I go to the worksheet where the array is and use the "Find" tool, it finds the value. When I return to the worksheet where the vlookup formula is, the formula works for that check number I have run find for. Nothing I have tried has work, format painting from spreadsheets that work, copying formulas over, rewriting formulas. This month has more rows than the prior months by about 2000 or so, with a total of 3800. Any help would be useful. I have attached the formula below:

=P4+VLOOKUP(A4,ISIS!A4:L3819,12,FALSE)

Where p4 is a simple dollar value I wish to add to the vlook
up (and this works in prior months)

Column A is the the check number in question, in both work books

Thanks in advance

 

[DonkeyOte]

are the data types consistent -- ie is A4 a number and ISIS!A4:A3819 numbers ?

do the following

=ISNUMBER(A4)
=ISNUMBER(ISIS!A4)

what are the results

 

[Cypdog]

They both return True and are both formatted as general. On the advice of a friend I used text to columns to format them again to general. That worked for most of them and for those left over the using the find tool no longer clears them up. I will post again when I discover some discernable pattern. Thanks for your help, I appreciate it.

 

[Aladin Akyurek]

What result do you get - #N/A?

 

[Cypdog]

Yeah, I get #N/A. I think its due to repeating check numbers and vlook up grabing the first instance. I can clear that up. Thanks for your help, I do appreciate it.

 

[Cindy Ellis]

If your vlookup range is not relative, be sure to add $ to the lookup range, as follows:
=P4+VLOOKUP(A4,ISIS!$A$4:$L$3819,12,FALSE)
(This may not be the cause of your problem, but if applicable, you should make sure that the range is properly referenced.)
Cindy

 

[Aladin Akyurek]

Yeah, I get #N/A. I think its due to repeating check numbers and vlook up grabing the first instance. I can clear that up. Thanks for your help, I do appreciate it.

If retrieving multiple instances are appropriate, you need maybe to switch to:

=SUM(P4,SUMIF(ISIS!$A$4:$A$3819,A4,ISIS!$L$4:$L$3819))