Make sure that the service for search host controller is run under the correct domain account. Make sure its an account that has enough credentials and that the password does not expire! also make sure its a managed account within central admin
for details on managed accounts and password change: Click here
make sure that the account that your using is part of the local admin group as well!
users and computers to add the
managed user account to
Go to "active directory users and computers" -> select the account that
is a domain account that is used for the service -> right click the
account and select "add to group" -> click advanced and search for wss
-> it should show three groups... You need to select WSS_ADMIN_WPG and click OK -> OK and now it should have correct access.
what version of SharePoint your using?
as for changing the account or checking:
goto services.msc -> goto the service in question -> right click and
select properties -> within the new popup select on "log on" tab ->
change to an account that has the right privileges to run that service!
so what have we done?
1) made sure the account were using is managed within central admin so that password is auto changed and doesn't effect services and is now accessible when creating services through central admin to be selected as a service account
2) made sure it has the correct privileges on the server to run the queries or anything that needs elevated rights or resources only available as admin on the local server like local resources
3) changed the service to use the new account or updated account if it is not the correct one!
you can use the network account but it would still need the right privileges and is not adhering to best practices... you should have a new account that is a service account specific to search. please refer here
as noted the account Network Service doesn't have the right privileges and ideally you shouldn't elevate its privileges but rather create a new account through central admin and add it as a service account -> make sure its part of wss_admin_wpg and then change the service to this new account and do an iis reset and all should work fine!