You know the email exists. You remember roughly when it was and who sent it, and you're pretty sure what it said. So you search for it and get nothing.
A search of my own email did exactly that once. The email was there the whole time. They'd just put it differently than I remembered it. I'd remembered the gist in my own words and searched for those.
So that's the main thing I'd pass on. Search for what they would have actually written, not what you remember them saying, and if you're not sure, go wider.
In CaseRelief I'd start with the people and the dates, and leave keywords for later. You're way more likely to remember who was involved and about when than the exact wording. Put in the email addresses of the people involved and a date range around when you think it happened, with some room on either side. That alone usually takes years of email down to something you can sit down and read through.
If someone used more than one address over the years, add all of them. The address filter also matches part of an address, so be careful with anything short. Typing just gmail.com will pull in everyone who uses Gmail, which is a lot of people.
Under the addresses there are two checkboxes, "Sent from" and "Sent to". I added those today. "Sent from" keeps emails where that person is the sender, and "Sent to" keeps the ones where they were on the To or CC line. Most of the time you want both ticked so you get their emails and yours.
Then keywords, if you still need them. Unusual words work best, like a street name or the subject line of the thread. Common words like "soon" or "meeting" will match half your inbox.
A few short words are better than one long phrase. An email matches if it has any of your keywords in it, so a couple of different guesses at how they might have worded it will catch more than one exact sentence. It ignores capitals, and it matches inside longer words, so "pay" also catches "payment" and "repay".
Keywords only look at the subject line and the body of the email. They don't search inside attachments. If what you're after is in an attached letter, filter by person and date instead and read through the attachments. Their text is in the evidence file along with the emails.
Make sure your own emails are in there too. Your sent mail is half of every conversation. When you connect a live account, CaseRelief searches your sent mail along with your inbox (on Gmail it uses All Mail, which has both). If you're working from a downloaded file, check that your sent mail made it into the download before you count on it.
And when you find it, read the full email, plus whatever it was replying to. A keyword match only tells you where to look. Same with summaries, whether they're from an AI or your own notes. They keep the gist and lose the exact wording.
– M