lookup function between 2 files

I use lookup function between 2 files and it works fine. But after i close the file and open it again, the link won’t be updated and so I got error message #NAME?

what should i do?

From LibreOffice error codes page:

Code 525 #NAME?
Message invalid names (instead of Err:525 cell contains #NAME?)
Explanation An identifier could not be evaluated, for example, no valid reference, no valid domain name, no column/row label, no macro, incorrect decimal divider, add-in not found

Please show the lookup formulas causing the error message.

=VLOOKUP(D8,[4]baru!$b$1:$I$65255,8,0)

What’s your LibreOffice version? Apparently you saved in OOXML .xlsx format and it looks like you were hit by some bug fixed already.

Hello

your VLOOKUP() doesn’t refer to a second file, but a sheet named [4]baru within the same document, which in turn is an invalid sheet name, since sheet names may not contain the characters [ ] * ? : / \ or the character ' (apostrophe) as first or last character. This clearly explains why you got a #NAME? error.

I’d expect something like

VLOOKUP(D8,'file:///<path_to_your_secondfile>'#$<sheetname>.$B$1:$I$65255,8,0

PS: The ! separating sheetname from range makes me assume, that you got the formula from an Excel document.