A Subscriber must synchronize with the Publisher within the time specified in the publication retention period. If a Subscriber does not synchronize within this period, the subscription expires. For more information, see Subscription Expiration and Deactivation.
The subscription must be re-created and initialized before the Subscriber can begin receiving data changes again:
For information about creating subscriptions, see Subscribing to Publications.
For information about initializing subscriptions, see Initializing a Subscription.
If the subscription database contains changes that have not been synchronized with the Publisher, you can use the tablediff Utility to determine which rows are different in the publication and subscription databases. For information, see A Merge Subscription Has Expired and Changes Must Be Uploaded.
You can increase the publication retention period to avoid having subscriptions expire. Use caution in setting a high value, because this can result in more data and metadata being stored, which affects performance. For more information, see Subscription Expiration and Deactivation.