Unable to open the save.
This save was previously loaded with an older version of the mod, but has since been removed.

模组「Blueprint Sandboxes (2.6.2)」引发了无法恢复的错误。
请向模组作者反馈此错误。

Error while running event blueprint-sandboxes::on_init()
blueprint-sandboxes/scripts/sandbox.lua:287: attempt to index field '?' (a nil value)
stack traceback:
blueprint-sandboxes/scripts/sandbox.lua:287: in function 'GetSandboxChoiceFor'
blueprint-sandboxes/scripts/toggle-gui.lua:164: in function 'Update'
blueprint-sandboxes/scripts/toggle-gui.lua:127: in function 'Init'
blueprint-sandboxes/scripts/init.lua:22: in function 'Player'
blueprint-sandboxes/scripts/init.lua:42: in function 'FirstTimeInit'
blueprint-sandboxes/control.lua:38: in function <blueprint-sandboxes/control.lua:37>

Then I find why this happened:

-- Determine whether the Player is inside a known Sandbox
---@param player LuaPlayer
---@param surface LuaSurface
function Sandbox.GetSandboxChoiceFor(player, surface)
local playerData = storage.players[player.index]
if surface.name == playerData.labName then
return Sandbox.player
--------↓ line 287 ↓--------
elseif surface.name == storage.sandboxForces[playerData.sandboxForceName].labName then
--------↑ line 287 ↑--------
return Sandbox.force
elseif Factorissimo.IsFactory(surface) then
local outsideSurface = Factorissimo.GetOutsideSurfaceForFactory(
surface,
player.position
)
if outsideSurface then
return Sandbox.GetSandboxChoiceFor(player, outsideSurface)
end
end
return nil
end

Then I try add "playerData.sandboxForceName ~= nil", but not work.
Finally I add "storage.sandboxForces[playerData.sandboxForceName] ~= nil", and now I enter the save.

It might be the mod that's causing the problem(I'm not sure) : https://mods.factorio.com/mod/Kux-PersonalTeleport
With this mod, I can travel to any surface, such as any spaceship or blueprint sandbox. In fact, the blueprint sandbox is inaccessible and will only keep the character ghost on it.

Hope you fix it as soon as possible.