Nothing's changed on my computer that I know of, but it has been about 5 months since my last full backup. Today I wanted to create one, but it just aborts the backup while saving C: (Win10).
I've run chkdsk on C:, but it did not find any errors. I checked the VSS event viewer, but there were no VSS Events nor other events during that time.
Here's the exact error message I get:

The log file doesn't seem to have anything useful in it either. I'll copy that below, just in case I'm missing something.
Any ideas on what to try (besides rebooting, which of course was the first thing I did)?
Thanks!
(Gathering writer metadata...)
(Waiting for the asynchronous operation to finish...)
Initialize writer metadata ...
- Get exclude files
- Enumerate components
- Get file list descriptors
- Get database descriptors
- Get log descriptors
- Get exclude files
- Enumerate components
- Get file list descriptors
- Get database descriptors
- Get log descriptors
- Get exclude files
- Enumerate components
- Get file list descriptors
- Get database descriptors
- Get log descriptors
- Get exclude files
- Enumerate components
- Get file list descriptors
- Get database descriptors
- Get log descriptors
- Get exclude files
- Enumerate components
- Get exclude files
- Enumerate components
- Get file list descriptors
- Get database descriptors
- Get log descriptors
- Get exclude files
- Enumerate components
- Get exclude files
- Enumerate components
- Get exclude files
- Enumerate components
- Get file list descriptors
- Get database descriptors
- Get log descriptors
Discover directly excluded components ...
- Excluding writer '' since it has no selected components for restore.
- Excluding writer '' since it has no selected components for restore.
- Excluding writer 'Shadow Copy Optimization Writer' since it has no selected components for restore.
- Excluding writer 'MSSearch Service Writer' since it has no selected components for restore.
- Excluding writer 'BITS Writer' since it has no selected components for restore.
Discover components that reside outside the shadow set ...
Discover all excluded components ...
Discover excluded writers ...
Discover explicitly included components ...
Verifying explicitly specified writers/components ...
Select explicitly included components ...
* Writer 'Task Scheduler Writer':
- Add component \TasksStore
* Writer 'VSS Metadata Store Writer':
- Add component \WriterMetadataStore
* Writer 'Performance Counters Writer':
- Add component \PerformanceCounters
* Writer 'Registry Writer':
- Add component \Registry
* Writer 'COM+ REGDB Writer':
- Add component \COM+ REGDB
* Writer 'WMI Writer':
- Add component \WMI
Creating shadow set {9326983d-1716-4410-8064-71189b2b1fbf} ...
- Adding volume \\?\Volume{815cc9c4-4838-4f05-9f54-1e424a651ef9}\ [C:\] to the shadow set...
- Adding volume \\?\Volume{687be422-9e26-435d-aabe-e05696082f68}\ [R:\] to the shadow set...
- Adding volume \\?\Volume{dc4ced5b-1ed4-4214-b715-4ffb29ddef59}\ [F:\] to the shadow set...
Preparing for backup ...
(Waiting for the asynchronous operation to finish...)
(Waiting for the asynchronous operation to finish...)
Creating the shadow (DoSnapshotSet) ...
(Waiting for the asynchronous operation to finish...)
(Waiting for the asynchronous operation to finish...)
Shadow copy set succesfully created.
Saving the backup components document ...
List of created shadow copies:
Querying all shadow copies with the SnapshotSetID {9326983d-1716-4410-8064-71189b2b1fbf} ...
* SNAPSHOT ID = {aa064db1-40fa-4044-897d-da4f381ba323} ...
- Shadow copy Set: {9326983d-1716-4410-8064-71189b2b1fbf}
- Original count of shadow copies = 3
- Original Volume name: \\?\Volume{815cc9c4-4838-4f05-9f54-1e424a651ef9}\ [C:\]
- Creation Time: 2/17/2023 2:53:58 PM
- Shadow copy device name: \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy14
- Originating machine: AsusZ170
- Service machine: AsusZ170
- Not Exposed
- Provider id: {b5946137-7b9f-4925-af80-51abd60b20d5}
- Attributes: Auto_Release Differential
* SNAPSHOT ID = {767626f4-f13d-4fce-a9a4-33db93cdf080} ...
- Shadow copy Set: {9326983d-1716-4410-8064-71189b2b1fbf}
- Original count of shadow copies = 3
- Original Volume name: \\?\Volume{687be422-9e26-435d-aabe-e05696082f68}\ [R:\]
- Creation Time: 2/17/2023 2:53:58 PM
- Shadow copy device name: \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy15
- Originating machine: AsusZ170
- Service machine: AsusZ170
- Not Exposed
- Provider id: {b5946137-7b9f-4925-af80-51abd60b20d5}
- Attributes: Auto_Release Differential
* SNAPSHOT ID = {289a1270-a072-48ba-9e6c-43d95e1e7fa0} ...
- Shadow copy Set: {9326983d-1716-4410-8064-71189b2b1fbf}
- Original count of shadow copies = 3
- Original Volume name: \\?\Volume{dc4ced5b-1ed4-4214-b715-4ffb29ddef59}\ [F:\]
- Creation Time: 2/17/2023 2:53:58 PM
- Shadow copy device name: \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy16
- Originating machine: AsusZ170
- Service machine: AsusZ170
- Not Exposed
- Provider id: {b5946137-7b9f-4925-af80-51abd60b20d5}
- Attributes: Auto_Release Differential