I added a spreadsheet to my working project and joined it to a feature class. I got the information I needed, removed the join and then removed the spreadsheet from my project. Now, I cannot open the spreadsheet in Excel unless I am not in ArcMap. If I shut down my Arcmap session (editing or not) I can open it. However, if I open the spreadsheet first and then open ArcMap it works...Can anyone help? I need to have it open at the same time I am in Arcmap.
it's a known limitation of Excel and ArcGIS. For now there is no way of having Arc and Excel having the same spreadsheet open at the same time, unless of course you make a copy of that spreadsheet.
I've had this same problem in the past as well. Once you've brought your .csv (spreadsheet) into ArcMap, then you need to right click on it and export. Save it into a file geodatabase (you can create one specifically for this if you don't have one). Then bring it into your map and you will be able to see both at the same time. ArcMap doesn't like working with a file that's not in one of it's native formats.