This issue can occur when the plugin initialization takes time during random seed generation in java.security file.
Please Check if this below steps helps:
1. Close all the PowerCenter clients.
2. Open java.security file from Informatica client's <Client_Installation_dir>\clients\java\32bit\jre\lib\security location.
3. Change the following property value from file:/dev/./random” to "file:/dev/urandom in java.security file.
Current Value: "securerandom.source=file:/dev/./random"
New Value: "securerandom.source=file:/dev/urandom"
Save the changes.
4. Open the Snowflake import wizard and see if it helps in reducing the time taken to open the wizard.