The most common and most likely answer to this crossword clue is the 8 letter word ARCHIVED
I've seen this crossword clue in Financial Times
A
R
C
H
I
V
E
D
More clues leading to the result ARCHIVED
Buddy explains!

The straight part
We know that "put in store" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case put in store = archived.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ARCHIVED mean?
ARCHIVED verb- To put into an archive.
- Having been placed into an archive.