"Complete Sprint", "Start Sprint", and /or Create Sprint" buttons disabled in the board

[Maria_Karbiner]

there is a post already, but I could not make it work 

https://community.atlassian.com/t5/Jira-Questions/quot-complete-sprint-quot-button-grayed-out-for-the-board-Owner/qaq-p/321817

• the users have admin roles in all affected projects 
• users are in a group with "manage sprints" and "start and complete sprints" rights
• no sub-tasks open in closed issues
• the board query is "project in ("project1", "project2") AND Team = 6 ORDER BY Rank ASC

[Petter Gonçalves]

Hello @Maria_Karbiner

Thank you for reaching out. Sorry to see you are facing a problem.

 To allow the management of a specific Sprint in Jira, you must have the Manage sprints and Schedule Issues permissions in all the projects returned by the board filter where the Sprint is located.

That being said, I believe the problem you are facing is caused by the lack of one or both permissions above in one of the projects returned by your board or/and added with that Sprint. These would be the steps to fix it:

1. Navigate to the board where the Sprint is located > ... > Board settings > General
2. Check what are the projects returned by your board:
   
3. Navigate to each one of the projects and add yourself with the Manage sprints and Schedule Issues permissions under Project settings > Permissions or ask a project admin to add you with those permissions, as mentioned in the documentation below:
   Managing project permissions 
   P.S: If you are using a complex filter in your board and Jira can not identify which projects are related to your filter, you must be added with the mentioned permission to ALL the projects in your site, or simplify the board filter. 
4. If that doesn't work, go to your issue navigator page and run a JQL search to find all the issues mapped to the Sprint:
   Sprint = "Sprintid" order by project
5. Then, doublecheck if the Sprint returns any issues from another project that is not related in your board query, adding yourself with the correct permissions on them.

For more details about the information above, you can check the documentation below:

Can't complete the sprint 

Let us know if these steps worked for you.