Agenda At Once allows multiple users to access same file from different computers. This is useful for teams working on same projects - they can share same to-do list, appointments schedule, notes and contacts. Additionally, you can use Assignees field combined with saved filters to specify who is in charge for specific task.
Multi-user support is simply achievable by placing database file to a shared folder available through Windows Network and using File | Open to point to it (example path: "\\SomeComputer\SomeFolder\TeamFile.aao").
Place file at public location
Make it available for all computers involved at least for most of the time. Avoid placing it on workstation local disk unless you are sure that access wouldn't be needed when specific workstation is off or it doesn't get restarted too often. Always-on file server would be ideal place.
Keep file small
Avoid inserting large embedded attachments unless it's really necessary. Delete old and unused items and do regular Compact and Repair.
Don't use local paths for attachments
When you use linked attachments, make sure you use UNC path so it can be accessible to anyone on the network. Generally, don't use paths such is "C:\MyFolder\MyFile.doc" as it will not work for other users (unless they all have "C:\MyFolder\MyFile.doc", which is usually still not what you meant to achieve). If file is and should remain on your local disk, use "\\MyComputer\MyFolder\MyFile.doc" instead (of course, MyFolder should be shared and visible on the network).
Make sure you adjust backup path
As backup path is written in the database, same directions apply as mentioned in previous tip. Additionally, it doesn't matter which computer actually executes backup - last backup time is also part of the database file, so other users will not be bothered again if it's not necessary.
Some operations require exclusive access to the file in order to be executed properly. For example, Compact and Repair and upgrading database (due to new version installation) are a critical low-level processes that require full control, and locking while doing backup ensures that each user's instance physically writes everything from the queue.
Locking is handled automatically by software. First, instance that needs full access sends a signal (lock request) to other users (small info window will appear to indicate this step). Other instances, when they detect this signal, temporary disconnect from the database, assuming that user is not in the middle of data editing. Similar info window pops up to inform what's happening. When all instances are disconnected, first instance continues with operation and, after it's done, sends a signal that database is available again. If locking fails from whatever reason, after 5 seconds you will see a warning window and you will be able to choose further action (Retry or Abort). After several unsuccessful retries (which is not what should happen often), you can call teammates and ask them to close Agenda At Once completely.
Combined personal and team usage
Usually you would want to keep private data separately from team data. There are two ways how you can accomplish this.
1. Use Database shortcuts
For easy switching between two databases, use Database Shortcuts. Please note that, if you choose this method, only alarms defined in currently active file will be executed.
2. Use two (or more) instances
To avoid drawback from first method, you can turn off Allow one instance only option and start Agenda At Once twice - one instance for each file. It's very lightweight application when it comes to resource consumption so system performance won't suffer because of this. If you wish to keep different personal settings for each instance, copy application to another folder. This way second instance will use own .ini file, similarly as in Portable device usage.