Problem

Even though the Collaborative Editing management page reports the connection between Confluence and Synchrony as stable, you are unable to edit pages with this feature enabled.

The following error can be found in atlassian-synchrony.log:

Having failed to acquire a resource, com.mchange.v2.resourcepool.BasicResourcePool@24f7d161 is interrupting all Threads waiting on a resource to check out. Will try again in response to new client requests.
com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@97422f3 -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception: 
java.sql.SQLException: The BUFFERDIR connection property is invalid.
    at net.sourceforge.jtds.jdbc.JtdsConnection.unpackProperties(JtdsConnection.java:1286)

Cause

The BUFFERDIR is a directory used as a temporary data holder for the connection between the application and the database. When using Tomcat as a web server, this directory is always the CATALINA_TMPDIR, which corresponds to the temp folder inside of Confluence Install. You can find more information about the Confluence directories here:

• Confluence Home and Install Directories

If Synchrony is unable to access this folder (<confluence-install>/temp), it will not be unable to communicate with the database and the editor will not load as expected.

Resolution

1. Check that the directory <confluence-install>/temp exists
2. Ensure that Operating System account which is used to start and stop Confluence has full read/write/execute permissions on this directory

3. If you are on Windows and you've added the java.io.tmpdir property in <confluence-home>/synchrony-args.properties to point to <confluence-install>/temp, please make sure the path uses double backslashes instead of a single backslash. For example:

   java.io.tmpdir=C:\\Progra~1\\Atlassian\\Confluence\\temp

    Reference: Editor fails to load in Confluence 6.x due to 'Could not initialize class org.xerial.snappy.Snappy' error.

4. Once those items are checked, restart Confluence and Synchrony should be able to reach the database