Restore points vanishing, cannot increase space

Restore points are vanishing for reasons I cannot determine. Apart from patches and RPs when none has been done for seven days (not often) I do a manual RP once a week. If there is not enough room my understanding is that the old RPs are deleted first. Instead, I have a handful of RPs when I bought the box six months ago, one in July, and then the weekly and MS patch RPs. An attempt was made to increase the disk space usage for RPs and there was an error message:
Could not apply the settings for the following reason: The filename, directory name, or volume label syntax is incorrect (0X8007007B)
The SSD (OS and software) has a lot of space, as do the USB HDs which I use for data.

Could someone please advise me what is happening and how it can be fixed? TIA

PNG file showing status.

The OS and software are on the SSD C:. Data is on the USB drive Q:. The setting is 5.42% or 6.96 GB. As far as I'm aware the OS has been activated. I've been getting MS Win 7 patches most weeks, such as five days ago, 100 MB or so. Absent a way of stopping the RPS from vanishing, could I copy the RP folder to Q: , and then if I need a particular RP move that folder back to C:? This is not really desirable as I delete all but the first RP of the month after six months, and after 12 months I'll have RPs at three month intervals. That's the plan at this juncture.

Thanks. I had guessed that an OS-related function such as Restore Points should be on the same drive as the OS. The Q drive was plugged in and set up, and was not made active by me. The OS must have done this. The box boots with and without the Q drive. The SSD seems to be needed.

I'm unsure how to remove the active flag on Q. While looking for a way to do this the following screen came up:
Ooops, can't put the PNG here. No matter

That is what I saw when the screen was opened - I have not changed anything. Can you please advise me how to remove the active flag? The advice in the link is old but seems to be current
How to change active partition without removing data from partition?

Thank you for your reminder about RPs not being backups. I have multiple full BUs going back for ages. The manual RP and a BU are done one a week, then copied to multiple places geographically different. So far so good. Data loss does not appeal.

Tharwatime said:

I'm unsure how to remove the active flag on Q. While looking for a way to do this the following screen came up:
Ooops, can't put the PNG here. No matter

That is what I saw when the screen was opened - I have not changed anything. Can you please advise me how to remove the active flag? The advice in the link is old but seems to be current
How to change active partition without removing data from partition?

Here's our tutorial,

Partition - Mark as Inactive

Thank you both. I made the command line changes as advised and it seems to have worked. My command screen is all but identical to the screen shots in the tutorial, with Q where the D is. I'll have to wait and see if RPs continue to vanish. I don't want to change the RP disk size as I prefer to see if one thing works. If the fix you you suggested works then I know that the problem was due to to the Q drive being active.