Can you upload some pictures? Snip & Sketch

Look in the table, what is different about that one record? Is it missing a relationship or have a wrong number or letter somewhere? Anything that sets it apart from the others?

Actual story here.  I once had a similar issue. Not unlike you, every time I ran a query my db failed.
Turns out it was because of my customers name.  It was Ron True.  Because of his name my query stopped when ever it hit his record. Really goofed with my head for awhile.

Long story I know, but look at the actual data you are putting in.  What is different?  If you enter another vendor - not the one you are currently entering that fails,  does the different one work?

If so it might be the data.  If not, it might be your tables, forms, or code that are preventing it working.
Maybe a validation rule?

If you can, blocking out any sensitive data of course, please give us some additional detail and even screenshots.

Adam - once again! LOL  
We are BORG....

Lol

Thanks for all of the responses. I found the problem. It was because I was using an "apostrophe" in the name of that particular Vendor. Apparently, access does not like the use of an apostrophe in a name. Once I removed the apostrophe, problem solved.

That isn't really a long term solution as another Vendor could still be entered that contains an apostrophe. I am assuming your form is opened like this:
DoCmd.OpenForm "VendorF",,, "VendorName=" & VendorName

Try using Double Double Quotes like this:
DoCmd.OpenForm "VendorF",,, "VendorName=""" & VendorName & """"

Or instead of using the VendorName, use the ID:
DoCmd.OpenForm "VendorF",,, "VendorID=" & VendorID

This is why I've been saying for years to use the double-double quotes. Don't use single quotes, even though you CAN.