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A site cannot install or find plugins and themes

Short answer: by default, GrabWP blocks site admins from installing, updating, or deleting plugins and themes (DISALLOW_FILE_MODS) so client sites cannot upload arbitrary PHP code. A platform operator can manage extensions for a site from the main site under Tenancy > All Tenants (Plugins & Themes), or allow file modifications globally or per site. Needs: Free

Symptom​

A site owner or operator notices one of these behaviours on a client site:

  • In the site's wp-admin, Plugins > Add New and Appearance > Themes > Add New are missing, or the Plugins and Appearance menus are hidden completely.
  • A newly created isolated site has no active theme until one is installed, matching the hint on Tenancy > Pro Settings > Isolation:
    • Isolated sites start without themes. Install one under Tenants > Plugins & Themes after creating the site.
  • A third-party premium plugin that is licensed on the main site asks for a license key again inside a client site.

Cause​

What you seeWhy it happens
No Add New button under Plugins or Appearance in site adminDisable Install Plugins & Themes (disallow_file_mods, which sets DISALLOW_FILE_MODS) is turned on by default under Tenancy > Settings > Tenant Capabilities.
Plugins or Appearance menu is completely absent in site adminHide Plugins Menu (hide_plugin_management) or Hide Appearance Menu (hide_theme_management) is turned on in Tenancy > Settings > Tenant Capabilities or in the site's Overrides tab.
Appearance shows Customize, Menus and Widgets but no Themes, and opening the Themes screen says Themes are managed by your host.Hide Themes Screen (hide_theme_switching, Base 1.1.15 or later) is turned on. Site admins keep customizing their current theme but cannot browse, install or switch themes.
GrabWP and SQLite plugins do not appear in the site's plugin listHide GrabWP Plugins (hide_grabwp_plugins) is turned on by default so site admins cannot see or deactivate platform plugins.
New isolated site has no themes installedWhen Level of isolation for new sites is set to Advanced (or Custom with Give each new site its own themes), the site gets its own empty themes folder and starts without themes unless cloned from a template.
Changing Tenancy > Settings has no effect on a siteDISALLOW_FILE_MODS or DISALLOW_FILE_EDIT is already defined in wp-config.php before GrabWP loads, which overrules the settings screen.
Third-party premium plugin is unlicensed on the siteEach site has its own isolated database tables and options, so a license activation saved in the main site's database is not shared with other sites.

Check​

  1. In the main site admin, go to Tenancy > Settings > Tenant Capabilities and check the switches for Disable Install Plugins & Themes, Disable Plugin & Theme File Editor, Hide Plugins Menu, Hide Appearance Menu and Hide Themes Screen. The Tenant file safety card on Tenancy > Status sums up whether site admins can add code (see Tenant file safety warning).
  2. If GrabWP Pro is active, go to Tenancy > All Tenants, hover over the site, and open its Overrides tab to check whether this site overrides the global Disable Install Plugins & Themes setting or displays a constant pin notice from wp-config.php.
  3. Open the site's Extensions tab (click Plugins & Themes on the site row under Tenancy > All Tenants) to see which plugins and themes are installed for that site.

Fix​

Install plugins or themes from the main site admin​

The safest way to give a site a plugin or theme is from the main site admin:

  1. Go to Tenancy > All Tenants.
  2. Click Plugins & Themes on the site row (which opens the Extensions tab).
  3. Activate, sync, or install the required plugins and themes for that site from the main site.

Allow a trusted site to install its own plugins and themes​

Only turn off Disable Install Plugins & Themes for site owners you trust completely, because anyone who can upload a WordPress plugin or theme can execute PHP code on your server.

  • For one site only (Pro): go to Tenancy > All Tenants, open the site's Overrides tab, set Disable Install Plugins & Themes to No, and click Save Overrides.
  • For all sites: go to Tenancy > Settings > Tenant Capabilities, turn off Disable Install Plugins & Themes, and save changes.
  • If a warning says the constant is already defined in wp-config.php, remove the manual define( 'DISALLOW_FILE_MODS', true ); line from wp-config.php so GrabWP can manage it.

Third-party premium plugin licenses on client sites​

Whether one third-party plugin license covers multiple sites depends on that vendor's licensing terms and domain checks. If the vendor allows multi-site or template use and does not lock activation to a single hostname, activate the plugin on a template site and clone that template when provisioning new sites.

Tenant file safety warning​

Since Base 1.1.15, Tenancy > Status > Plugin General and the setup wizard's Server check include a Tenant file safety card. It shows OK with Tenant admins cannot install or edit plugin and theme code. while both protections are on.

It shows Unsafe with Tenant admins can install or edit plugin and theme code. That code runs on this server and can read the secret keys every site shares. when any of these is true, and lists each cause:

CauseWhat the card says to do
Disable Install Plugins & Themes or Disable Plugin & Theme File Editor is off on Tenancy > Settings > Tenant CapabilitiesTurn on %s in Settings. Click Open Settings.
Code that loads before GrabWP, usually wp-config.php, sets DISALLOW_FILE_MODS or DISALLOW_FILE_EDIT to falseChange the value to true or remove that line.
A Pro per-site override turns one of the protections off for a siteIn that site's Overrides screen, choose Yes or Use global setting. This line needs Pro 1.1.18 or later together with Base 1.1.15.

The card is a warning only. If you turned a protection off on purpose for a site you trust completely, you can leave it.

Still stuck​

If you turned off Disable Install Plugins & Themes and verified wp-config.php, but the site admin still cannot install plugins, send screenshots of Tenancy > Settings > Tenant Capabilities and the site's Overrides tab. See What to send when you ask for help.