If you move a SQLCE database from one platform to other, it's first SqlCeConnection.Open() takes more time and also increases the database file size.
The Reason: For an index on string type columns, SQLCE uses LCMapString API to get the normalized sort key. LCMapString API behavior will be different for different NLS sort versions. NLS sort version is different for Desktop Windows OS and WM/WCE. During the first database connection open, SQLCE rebuilds all indexes if there is a NLS sort version mismatch with the last accessed OS platform. Index recreation requires space on database file and hence the database file size will be increased. You can use Compact()/Shrink() API to get the database file with approximately old file size. Because of this index recreation, first database connection open takes more time as it has to rebuild all indexes.
Note: If your database doesn’t have any indexes you will not see above mentioned symptoms on first connection open.
Don’t inter-op SQLCE 3.0 databases between devices and desktop:
SQLCE started supporting desktops only from SQLCE 3.1 (3.0.5300.0) release. SQLCE 3.0 doesn’t have index rebuilding logic and the index re-creation was added during SQLCE 3.1 (3.0.5300.0) release as it is required to support platform inter-op for SQLCE databases. On desktop you can open SQLCE 3.0 databases, which were created on devices. Again If you open these databases on SQLCE 3.0 devices, your device app might receive an error/exception.
For example: Opening a SQLCE 3.0 database with SSMS will use SQLCE 3.1 bits on desktop and hence it would drop and recreate index data. When this file is copied back to device, index data may not be valid and receive an error/exception.