Number of items in "My Library" differs from the sum of the items in the collections. Why?
I am importing 10 collections all in the same library and each of the collections contains 10 items, which makes 100 items in total.
However, when I click on "My Library", where all the collections have been imported, on the right panel Zotero counts/displays only 95. It says "95 items in this view". I counted each collection multiple times, each one contains exactly 10 items and there are 10 collections, which makes 100 items in total, not 95.
On top of that, I can see that each of the 10 collections is being displayed as "10 items in this view" by Zotero. However, it sums only 95.
Why is Zotero doing that? I am going crazy. I've never had this issue before.
P.S. I haven't touched anything yet: haven't removed any duplicates or anything similar.
However, when I click on "My Library", where all the collections have been imported, on the right panel Zotero counts/displays only 95. It says "95 items in this view". I counted each collection multiple times, each one contains exactly 10 items and there are 10 collections, which makes 100 items in total, not 95.
On top of that, I can see that each of the 10 collections is being displayed as "10 items in this view" by Zotero. However, it sums only 95.
Why is Zotero doing that? I am going crazy. I've never had this issue before.
P.S. I haven't touched anything yet: haven't removed any duplicates or anything similar.
In principle, Zotero collections are not folders, they behave more like tags. The same item (not a copy, really the exact same object) can belong in multiple collections. Thus, the total number of items will often be less than the sum of all collection counts.
https://www.zotero.org/support/collections_and_tags
I exported every single of the 10 results in .bib format.
My search-keywords were very similar, but well documented. There are for sure a lot of duplicates in the search results.
So if I understand correctly, Zotero might handle some of them as duplicates when displaying the final result? By the way, I counted the items hand by hand, there were indeed 95 instead of 100. It's not only a display error. For some reason, Zotero excludes 5 of them. But this would be weird - the "Duplicate Items" section is for removing duplicates, Zotero shouldn't be doing this automatically.
Hum. If you imported 10 files, indeed I would not expect Zotero to merge duplicates automatically.
Are you using any plugins? Maybe this could change the behavior in such a case.
Right now, the only other thing I could suggest is to try deleting your 10 collections, then importing just 1 file, then another one, then maybe another one... and see exactly when the numbers start diverging?
I don't want to admit it, but this is definitely my mistake. One of the .bib files was corrupt (I noticed that in the beginning). I deleted it and downloaded it again. But unintentionally, I saved it under another name (very similar to the target name). I didn't notice that and this is where the discrepancy between Zotero and my Excel count based on formulas was coming from.
However, I noticed that only after your suggestion to add the files one by one and to see where the diversion comes from! So thanks for your time and sorry that this wasn't a more "interesting" error. I messed up :)