INSTR cannot be found in VISA Resource List After Network Outage

[BugHunter5]

I have two Ruska 7050is that can be controlled running the same program from two different computers. Both computers were able to connect to the Ruskas and run the program up until a network outage where I believe a switch was replaced. Wiring was supposedly not changed. Ever since, the second computer has not been able to connect to the Ruskas at first (error is GPIB0::1::INSTR cannot be found in VISA Resource List). NI Max  on the second computer still shows the instruments properly, including INTFC and INSTR. On both computers, the VISA Interactive Control only shows INTFC (with the correct GPIB ports assigned to the instruments though), no INSTR, so I am not sure if that is correct.

However, if the program is run on the first computer, the second computer can run the program and connect to the Ruskas. 

I have tried repairing all NI packages through NI Package manager on the second computer but that did not fix the issue. For the first computer, when I try to access devices in NI MAX, there is a corrupt database error. I am working on getting admin access to reset the NI MAX database on the old computer, but in the meantime, can anyone give suggestions?

So, first computer: corrupt NI MAX database, but can connect to Ruskas

Second computer: Ruskas appear in NI MAX normally, but cannot connect to Ruskas immediately

1) Are the INSTR supposed to show in VISA Interactive Control, or is it normal just to have the INTFC with correct GPIB ports?

2) How does one computer connecting to the Ruskas allow the second computer to connect to the Ruskas?

[Iwa6]

The address "GPIB*::INTFC" refers to the controller side of the GPIB. (In the case of National Instruments' GPIB I/F, it refers to the GPIB I/F in controller mode connected to a computer, such as GPIB-USB-HS or PCIe-GPIB.)
Generally, users do not directly open and use the controller address.
The address of the instrument is "GPIB*::*::INSTR". The instrument can be expressed as "GPIB*::*" by abbreviating "::INSTR".
https://www.ni.com/docs/ja-JP/bundle/ni-visa/page/visa-resource-syntax-and-examples.html

I'm not sure what you mean by "switch", but are the two computers and the two Ruskas connected independently? (One computer and one Ruska)
There can be no multiple controllers (control side) or instruments with the same address number on one GPIB bus (a group of computers and instruments connected in a daisy chain).

[BugHunter5 · Accepted solution]

Thank you for your response.

After I got admin access, I saw that the NI-488 package was missing from NI Package Manager on the second computer. I can now add the devices to NI Max. I suppose the driver was corrupted somehow.