If these are files converted from a much older version (such as FileMaker 5 or 6), sometimes they contain an external file reference that takes an extremely long time to open. If you have a copy of your file that predates the change where this started happening, open it and use Manage | External Data Sources and check for Asterisks or references that attempt to locate a file by IP address where the IP Address is no longer the location of the file.
If you don't have such a copy, you might try opening the file and then waiting for up to 20 minutes to see if it finally opens.
Also, do you have any script in this file set up to run when the file opens? Is there any step such as Close file or exit application in this script?
Thanks PhilModJunk. I'm kinda computer illiterate.
This time I opened FileMaker Pro 10 and left it open for 30-60 minutes. This message came up:
"Communication with the host was interrupted and could not be re-established. All affected windows will be closed."
As I mentioned earlier, FileMaker will not open. When I roll my mouse over the FileMaker icon in the taskbar, the image above appears - it's supposed to give me a preview of the screen but instead it looks jumbled and messed up.
"communication with host" indicates that you are connecting to a file hosted over the network. Pull a copy of this file onto your local workstation and see if you can open it directly on your machine. If all else fails, you may have to revert back to your most recent back up copy that doesn't have this problem and try again, checking each change (and making back ups at each point) until you identify the specific change that creates the problem.