Summary	Qlik Sense Connectors are missing from the Data source except few REST connectors.
Product	Qlik Sense
On this page	1 Resolution 1.1 Solution 1 1.2 Solution 2 2 Cause 3 Related Content 4 Environment
Related Content	https://community.qlik.com/t5/Official-Support-Articles/Qlik-Sense-Data-Connectors-are-missing/ta-p/2426284

Resolution

Repair Qlik Sense with the Qlik Sense Setup file (identical version).

Obtain a copy of the folder "C:\Program Files\Common Files\Qlik\Custom Data\" from a different, but working Qlik Sense Enterprise on a Windows environment (identical version). A test installation can be set up to obtain it.
Replace the files/folders with the copied version. This action needs to be carried out on all nodes if it is a multi-node environment.

Cause

The Connector folders or executables are corrupted or deleted.
Connector folders or executables are being scanned and removed from their path. Therefore, it is mandatory to exclude Qlik folders if any scanning software is present on Qlik Sense Windows machines. For more information about exclusions, please refer to the document titled Qlik Sense Folder And Files To Exclude From Anti-Virus Scanning