That usually indicates that the emails in question have been deleted but he search index is not updated. The most common cause of that is an anti virus product claiming to find a problem and you answering it to fix it automatically.

This article will assist you on rebuilding the search database https://support.mozilla.org/en-US/kb/rebuilding-global-database

Matt: I am not a computer nerd (this is not an insult). I could not find my "profile". I use Win 10, latest update. I have Malware Bytes Premium and Eset anti-virus. This is a weird problem. On further searches, all the requested emails come up. Some do not. I'm perplexed. The problem started when I was searching for a Staples store receipt that I needed to return some merchandise. In fact, the missing emails were addressed from "staplesreceipt@staples.com". All I got in the window below was a donate to Thunderbird request. It seems to only occur on '"some" commercial email senders, not ones that I know personally. So now I suspect that the problem only exists with some commercial email senders. But I still do not know how to find my Thunderbird "profile". i do not understand how to actually "find" the file or program to locate it. Thank you, Matt

go to the help menu. Select Troubleshooting information. Click the show button beside the profile entry.

Now you have found it, Close Thunderbird and continue with the instructions.

Thanks, Matt.

Matt: There were not "instructions" on the selected screen. here is what the page said: Thunderbird Version 52.7.0 User Agent Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 Profile Folder (Local drive) Application Build ID 20180322145026 Enabled Plugins about:plugins Build Configuration about:buildconfig Memory Use about:memory Profiles about:profiles Mail and News Accounts ID Incoming server Outgoing servers Name Connection security Authentication method Name Connection security Authentication method Default? account1 (pop3) pop.verizon.net:995 SSL/TLS Normal password smtp.verizon.net:465 SSL/TLS Normal password true account2 (none) Local Folders None Normal password Crash Reports Report ID Submitted bp-70dd2f15-ab00-41e9-ae13-866ff0180217 2/17/2018 bp-561e5194-08e3-42fc-9401-52fba0180215 2/15/2018 bp-5748bfe0-0012-43b5-9410-1a6360180122 1/22/2018 bp-148ff04d-b4c1-4635-8606-6e7e40180112 1/12/2018 bp-cc98ae52-b2ee-4041-bdde-67e970180108 1/8/2018

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Between Profile Folder and local drive in the text you just posted. Is a button that literally says "open folder" (Local drive)

about three posts back I gave you a link to instruction to rebuild the global database. SO now you have found a way to locate the profile folder you can continue with them.