Primary Key dropped on my table.

[walsh61850]

Why does my table lose its primary key?  I set a primary key to a number and date, so as to NOT allow duplicates for that day.  Every now and then, I have duplicates.  When I look at my table in design mode, the primary keys are not set.  I cannot find any reason for them to be reset as no one else has access to my tables.

[#2]

You may have some form of corruption. This is never supposed to happen.
Do an Office Repair, followed by creating a new database and copying your data over.

[#3]

OK.  I will do that.  What could cause the corruption.  Other tables do not seem to be affected.@Tom_van_Stiphout 

[#4]

@walsh61850
Corruption is caused by different things, so we can only offer possibilities.
Someone shut down their computer while an Access write operation was in progress.
A network interruption occurred while an Access write operation was in progress.
Stuff happens.
Two users tried to update the same record at the same time, and the conflict wasn't resolved correctly.
Other stuff happens, too.

[#5]

Thanks. I was afraid of that being so.