Files in SharePoint 2016 cannot be searched

Question

Files in SharePoint 2016 are not searchable and I have crawled the content source

Answer 1

@Xiangtian Yang There are some reasons which may cause this issue, so, let's verify the followings firstly:

1. Are all files not be searchable on your site or just some files? If just some files, could you please compare their differences.
2. Is there any error displaying when searching? If yes, please provide more information about it.
3. What keyword did you use to search? File name or others?
4. Are you using library search or site search or search center to search these files?
5. Does this issue happen on other libraries or lists?
6. Does this issue happen on a specific site or all sites of your farm?
7. Check your search topology, make sure they are running like the below:
   
8. Did you ever use Search to search files? Did you run a crawl after uploading these files? Please go to Central Administration->Search Service Application->Crawl log->[your content soruce], check if these files are crawled, like the below:
   
9. Please make sure you have at least Read permission on these files that you want to search as search has security trimming.
10. Did you configure AAM(alternate access mappings) on your farm? If yes, you need to make sure you are using the default zone URL in your content source.
11. Try to reset the Index, then run a full crawl, after finishing, search again.

Please have a check and let's know the result.

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Updated on 2/5--------------
@Xiangtian Yang Based on the ULS log file, there is something wrong with the query processing.

Firstly, please make sure there is enough free disk space for your Search server which hosts the Query component. You can check SharePoint Server 2016 hardware requirement as the article.

Secondly, double-check the search topology, make sure all are running like the below, especially for "Query processing".

Go to Application Management->Manage services on server, make sure all search services are started:

Also, please try to restart "Search Host Controller Service" and "Search Query and Site Settings Service". After that, test again.

If the issue still exists, please use the following PowerShell commands to restart search service application:

net stop osearch15  
net start osearch15  

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