I'm not seeing anything jump out that would cause your conflict message to not show up.

If you're not seeing anything, then I would suggest commenting out the "On Error Resume Next" and try your edit again to see if an error pops up and what error message there is may help you figure out what is going on.

If still no error message, I would add a message box after the DLookup to see what information is being requested and checked, for example:

msgbox("ID: " & ID & vbnewline & "GroomerID: " & GroomerCombo & vbnewline & "ApptID: " & ApptID & _
            vbnewline & "ApptDate: " & ApptDate & vbnewline & "EndTime: " & EndTime)

This will show you what is going into and coming out of the Nz/DLookup which could in turn tell you if the problem is in your code or in your form.

Am I missing something, or is the problem possibly that you are looking for an "old" EndTime that ends after the "new" EndTime, but your "new" example with 10:35 am ends after the "old" EndTime at 10:20 am?

Thanks Donald, I will try those things to see what it is doing vs what I want it to do...  Lars... Maybe?  I wondered that also... i will also play with the time.  I think that is what happened in the video as well though and it worked for Rick... but I also know just because Rick does it doesnt mean I can... for whatever reason... lol

As I sit here sipping coffee and nursing a migraine I am thinking I really also need to take into account drive times in my scheduling overlaps... need time to get from one end appointment to the next beginning appointment... since my daughter is a mobile dog groomer... So many moving parts to remember to include.  sometimes I dont realize I spaced out for a long period of time because in my head i am playing out scenerios of what could happen or might happen that i need to work out after i get the basics to work.  My husband will wave his hand in front of my face and I am like what?!?  I am thinking!  

Lars... I tested your theory and put the dates inside the start and end times and it let me do it.... so that isnt it...   so gonna try the things Donald gave me to try.

Okay Donald...  Nothing happened when I messaged the On Error.  So I added the MsgBox code in the after update for EndDate.  And nothing happened... no MsbBox... What I took from that is the AfterUpdate is not working which I guess could maybe be because it calculates after ApptDate updates?  Seems strange ... even tabbing through doesnt trigger anything.  So I moved the MsgBox to the after update event for ApptDate since that is where I am initially making the change and that DID give me the MsgBox.  All of the things messaged are correct, except the ID does not change from 0.  So no conflict is being triggered.  but it seems like it should since the new appointment date and start and end times are inside of the other date and time... total conflict.  I am so confused...  I will upload the pics so you can see what I am seeing

okay... so... I am listening to the lesson 33 again and Rick says those items are coming from the Table... and because EndTime is a calculated field it is not on the ApptT table.  So it is not able to compare the EndTime.  Can I reference the field in that record that was just calculated?   I am also wondering... I mentioned that I need to think about including the drive time to each appointment in the checking for overlapping appointments.  I have the address for each appointment in the customer table.  Is there a way to say to have Access calculate the drive time to the next appointment so that can be taken into account? I know access can go out to the web and get stuff... wasnt sure if it was capable of accessing mapping things?

If Endtime isn't in the table, then you'd have to either remove it from the dlookup or put the formula in place of the the "EndTime" field in the dlookup such as (if the appointment time is 2 hours and 30 minutes):

Replace "EndTime > #" & EndTime.... with something like "(DateAdd(""h"",2,ApptDate) + DateAdd(""n"",30,ApptDate)) > #" & EndTime...

Unfortunately, I haven't purchased the work order seminar as yet so I don't currently have videos to follow along with :( Richard does so similar scheduling conflict resolution with a reservation system in Access Developer 24, but in those lessons, the End Date is stored in the table.

Beyond that, it would probably better for me to tap out on this one and let one of the other more experienced students (or someone else who has the work order seminar) step in as I will likely only confuse us both trying to guess at it.

Sorry, Don