When a Custom Value is deleted, it is permanently removed from DESelect and cannot be recovered. 

To prevent this issue from happening we recommend:

Creating a copy of the Selection, the Custom Value will also be created and serve as a reference if you choose to recreate it.

Create a Shared Custom Value (only available in DESelect Segment Advanced Edition). Follow this link to learn 

How can I recover a deleted Custom Value?

How can I limit the results from multiple data sources/tabs within a Selection?

Date Difference Custom Value

Transform Date Custom Value

Timestamp Custom Value

Fixed Custom Value

How does the Update Data Action work in the Output Step?

How does the Append Data Action work in the Output Step?

How does the Overwrite Data Action work in the Output Step?

Can I build an Aggregation Custom Value grouping on two fields?

How does the Advanced Mode of Aggregation Custom Values work?

Can I reuse my Custom Values in any Selection?

What are the available Data Actions when configuring the output of a Selection?

What do I need to consider when editing my Target Data Extension?

Can I browse through the folders to search for the Target Data Extension that I want to use?

Row Number Custom Value

Can I combine Data Extensions that do not have any matching columns?

How to use multiple fields as the unique field in deduplication?

What field types are compatible for mappings?

Supported SQL functions

Aggregation Custom Value

How to create an Apply any function (SQL) Custom Value?

Can I do A/B testing with DESelect?

What is executed first, Sort and Limit or Deduplication?

Apply formula to a field Custom Value

What is a Custom Value?

Can I edit the fields of a Target Data Extension in DESelect Segment?

How can I deduplicate the results of my selection?

How to create a Target Data Extension on the fly in DESelect Segment?

How to map my source data to my Target Data Extension?

How does Automap work?

Dynamic Custom Value

Is there a limit on the number of Data Extensions that can be created?

How to set and populate my Target Data Extension?

What are the Data Actions available when saving data into a Data Extension in DESelect Segment?

Step 2: Target Definition

Version

DESelect

How to use Data Views with DESelect?

How to use Data Views in DESelect?

Can the user define any relationship between Data Extensions that (s)he wants?

What data can DESelect Segment use?

How does DESelect Segment work with Synchronized Data Extensions and Data Views?

How do I create my first Selection?

When to use In/Not in Results instead of adding the Data Extension to my Selected Data Extensions?

Does In/Not In filter types support Number and Decimal data types?

How to browse/ search your Data Extensions

How to quickly change the relations between my Selected Data Extensions?

Can I directly convert a date field into a different timezone in the Filters section?

Can I save and reuse a set of Filters?

Can I add Synchronized Data Extensions into DESelect Segment?

What are Behavioral Filter Sets?

Why DESelect Segment adds a "OR field IS NULL" to the SQL Query when creating DOES NOT CONTAIN filters?

Can I stop the run of a Selection that is in progress?

How can I combine 'OR' and 'AND' statements in DESelect Segment?

How to use In and Not In filter types

How to use Equals and Is not equal to filter types?

How does Contain and Does not Contain filter type works?

How does Contains one of and Does not Contain one of filter type works?

How does Begins with and Ends with filter type works?

How does Is Empty and Is not Empty filter type works?

How does Is smaller than and Is smaller than or equal to filter type works?

How does Is greater than and Is greater than or equal to filter type works?

How does Between and Not Between filter type works?

How does is after and is before filter types works?

How does in previous and in next filter types works?

How does calendar and relative filter works?

How to use In Result and Not in Result filter types?

Step 1: Selection Criteria

What is a “Selection”?

Can I copy my Selection to another Business Unit?

What is a Waterfall Selection?

Can I set my Selection as a template?

How can I modify the name my Selection?

Can I have an overview of all my scheduled Selections?

How to copy Standard or Shared Custom Values inside a Selection?

Can I create a Selection using a template?

Can I copy my Selection?

How to save folders as favorites in DESelect Segment?

How to reorder columns in the Overview page?

Step 0: Selections Overview

How do I access DESelect Segment?

Getting started with DESelect Segment: Step-by-Step Examples

How can DESelect Segment help you?

What are the features included for DESelect Segment Free?

Can I use List in DESelect Segment?

Getting started

How To Use DESelect Segment

Whitelisting DESelect Segment IP

Enable DESelect Segment in new Business Units

How to configure a user to access DESelect Segment?

What are the minimum SFMC permissions to use DESelect Segment?

How to configure Schedule Selections in DESelect?

Install DESelect Segment in SFMC

Transferring user licenses

How do I install DESelect Segment in SFMC?

How do I install DESelect Segment Free?

Troubleshooting Guide: Unable to Install DESelect Search via AppExchange on Salesforce

How do I unistall DESelect Segment Free?

Installing DESelect Segment in Salesforce Marketing Cloud

Recommended Browser Settings

How to add the Synchronised Data Extension to my DESelect Segment account?

Why don't I have access to the Admin Panel?

DESelect Segment Free Limitations

Whitelisting DESelect Search IP

Other

Setup DESelect Segment

Overview

Where can I see the performance of my sends in DESelect Engage?

How to create a new Send in Journey Builder?

Can I import existing Journeys into DESelect Engage?

What are the Reporting Capabilities in Engage?

How do I know which contacts have been included or excluded for a past Send?

How can I check all the Sends for a specific contact?

How to automate retries of Sends using Engage saturation control in a Journey?

What is List View?

What is Calendar View?

How to create a new Send?

How to use DESelect Engage

What is a Priority?

What is a Rule?

What is a Channel?

What is a Contact Category?

What is a Campaign Type?

What are the available user roles in DESelect Engage?

What does the DESelect Engage Implementation Process look like?

What are the minimum SFMC permissions to use DESelect Engage?

How do I enable the required Extract Types for DESelect Engage?

Creation of Installed Packages

Creation of a Contact Categories data extension

Set up User Access to DESelect Engage

DESelect Engage Implementation Guide

Does DESelect Engage work on a Business Unit level or Enterprise level?

Do I need to add all Sends to the Campaign Calendar in DESelect Engage?

What happens if a Send goes through Journey Builder on a different date than the send date in DESelect Engage?

How can I overrule saturation control to make sure a certain campaign Send is sent?

How can I do A/B testing on what the most effective saturation control rules are in DESelect Engage?

How does DESelect Engage decide whether somebody should receive a Send or not?

How does DESelect Engage deal with always-on journeys, where you don't know in advance who will enter the journey?

How does DESelect Engage deal with unplanned Sends?

How does Engage deal with multi-wave journeys / sequences?

Is there a way to test Engage without actually impacting the Sends?

Can Engage retry a campaign Send if a contact is oversaturated?

Can Engage support/apply saturation control on Sends that are happening outside of SFMC?

Do I need to add the Engage Journey Builder component if I want to overrule saturation control?

What's the difference between Einstein and DESelect Engage?

Can Einstein Send Time Optimization be used in combination with DESelect Engage?

Can DESelect Engage be used with Email Studio or Automation Studio?

Does DESelect Engage take care of the sending of my messages?

How do I know which contacts will be excluded from a planned Send?

What are Tags used for?

How does Engage deal with retrying a Send within a journey?

What to do when I change a rule?

How to optimize your Sends using a retry?

Can I make sure that the audience of a future Send is included in the prioritization calculations before I have the actual audience ready?

What is DESelect Engage?

I added a new Send to DESelect Engage's calendar and it's not colored yet, why?

How to solve the Engage Journey Builder component loads for ever and never retrieves Send information?