You have reached the maximum number of users
AccountEdge tracks each User’s ID as they enter and exit your company file. It does this using a file named Lock####.FLK. The Lockfiles are numbered Lock0001-Lock0010. AccountEdge creates one Lockfile for each file you have opened. The Lockfile contains the name of the file, as well as the User-Ids and permissions of each User in that one company file. The number of licenses (seats) your company has determines the maximum number of Users/IDs who can open a company file at one time.
Check to see how many users are active in you company file. From the File menu, select Active Workstations. Next, check to see how many Users are allowed to be in your file at the same time. Find this out under Setup/Company Information. If the maximum number of simultaneous users has not been met, and you still cannot get into your company file, all users should Exit AccountEdge. From the Folder where your data file is located, delete files Lock####.FLK if present. There may be more than one lockfile. All may be deleted. If you are unable to delete those files, restart the machine that the LOCK####.FLK files are located on. This will release the "hold" against that specific file and will enable your users to enter the application as needed. For more information about lingering lock files and trouble opening your file please see this article.
If you require more than the maximum number of simultaneous users which you are allowed in the file currently, you can purchase additional workstation licenses to increase the number of simultaneous users. If you are using an old version of AccountEdge, you may need to upgrade your software. Call Customer Care (800.322.6962) for details.